could i get some advice?

heres a picture of him at 9 or so months in his " I saved a life bandana".(hes a blood donor)

I don't have much advice but I do know that he is doing exactly what this breed is meant to do.  I've always had to "manage" my dogs aggression issues.  It wasn't something that I could train away or trusted that I could reliably train away even if we tried.

I'm just curious how you ended up with this particular breed?  Aren't they pretty hard to find??  If you got him from a breeder maybe you could speak to him/her about this. 

But, the little I know about this breed is that they are super watch dogs and can be dangerously aggressive. 

I'm not trying to discourgage you at all, hey I've got a chow, LOL,  just speaking realistically.   I'm sure he could be trained to stop the aggression when you said, my friends mom weighs about 90 lbs and can call off her Rotties on a dime from a full almost attack like mode that they get in.  I just never trusted Willow would ever be that reliable and with something as serious as human safety it was easier for me just to manage the situation.

Did the behaviorist come to your home, or did you take Santo to her?
 
Since his behavior stems from having people enter the home, you need her to come to your home to really see his reaction.

Well, I'm a vet tech.. and one day one of our clients came in telling me that Santo was starting to figure out where he was on the totem pole. She had 1 male and 1 female pit and 1 male and 1 female pit/neo mastiff mixes. Needless to say the 2 males were dominant so Santo was getting beat up. She knew that iwas interested in the breed, but had never owned a presa before, so she asked if I would take him. Well as I said, he is the sweetest boy when we arent at home or in the car, so I took him some 3 months ago. I've owned dogs with "known behavioral issues" before, but I have never seen this kind of aggressive protection. He just goes off when someone comes inside, or if I'm walking him near the house and he sees anyone.
 
To answer your question Scout I took him to her for the consultation, shes like 45 minutes away from where I live so therefore even if she did do in-house training I think I'd be a bit too far away. I am however looking at other behaviorists a little closer to home to get somone to come here and for a 'second opinion'

I think a second opinion would be a good idea. If the behavior only pops out in your own home, that's where the consultation needs to be. It's hard to say if there's much you can do to change it - after all, it is a characteristic of this breed. But maybe they can help you get to the point where the dog does his warning bark, but at least listens to you when you tell him to stop.

I've owned dogs with "known behavioral issues" before, but I have never seen this kind of aggressive protection. He just goes off when someone comes inside, or if I'm walking him near the house and he sees anyone.

 
You really should do some research on this breed because this should of been expected.  This is what they are meant for.  I'd start a NILIF program with him right away. 

but frankly I cant expect my neighbors or my friends to willingly walk into my house with my 80lb puppy running right up to them barking/growling and acting like a jerk.

 
 Even my people-loving Great Danes bark and growl and carry on if strangers try to come into or near the house-- this is pretty normal behavior for most dogs regardless of breed. But surely you can train the dog to stop barking on command? or at least sit on command so you can put a leash on the dog and confine it while your visitor is there. Lots and lots of obedience training. You need complete and instant control over a dog of this size and power.

Um, with all do respect this is exactly what this breed was meant to do. Its liek trying to get a lab from retrieving. Its going to be really hard. I would say you need to find out who your friends are and get them to help you out with some serious visit exercises.
I read a article a while back that was similiar to yours and the behaviorist suggested this:
Have a friend stand a safe distance away from your front door (the trick is getting them to be as close as possible without your dog being on alert) lets say 15 feet. Walk your dog out of your front door to the person, have the person greet them ( no eye contact, just palin ole friendly greeting) and produce one of your dogs favorite treats. All three of you should then start walking back to your front door as the guest contiues to dole out treats and enter the house together. Have them sit and hang out as usual. If at any point the dog starts to growl stop you need to tell them its not ok. As owners we tend to use reassuring tones to calm the dog but in reality they may think you are condoning htem for their actions. Use a firm no nonsense tone.
This exersice should be used no more then two times a day and the guest should gradually get closer everytime. Bottom line is the dog should obey YOUR command over any instincts it may have.
This also works best in conjunction with the NILF program, google it if you have never heard of it. Your dog should never try to proceed through a doorway ahead of you, when you open a door does he bolt through? You can practice this anytime alone. Go to the door, give your dog the sit-stay command and try to open it. If your dog tries to go ahead of you close the door and start over. Reward appropriatly.
Now if your dog dosnt know the sit-stay commadn then general obediance is defintly required before you can address the other issues. A breed as strong, willful, and stubborn as yours needs structure, guidance and needs to know YOU are alpha. That may be why he is trying to establish rank now. A dog has no problem being lower in rank as long as their is no question that you are the boss. I'd love to see a picture, I just love this breed to peices!

I have already enrolled him in some beginner obediance classes because his previous owner never did, although the class itself doesnt start for almost another month. I am fully aware of what this breed is meant to do. I had spent countless hours researching the breed, looking at breeders, and trying to gain overall knowledge of what to expect from Presas well before the lady asked if I would take him. I know he is meant to be protective, I know he is meant to be suspicious of strangers, I infact WANT him to be, however I expect him to stop being aggressive once I've accepted the person(s) into my home.I had a rotti named Scarlet that was very protective of my brother and I growing up, unless it was a child, that would stand by the door with her teeth showing until someone(in the family) shook their hand and welcomed them inside.I cant expect him to be that calm about strangers, but I do want him to comprehend that when I welcome someone in he needs to trust my desicion to bring them into MY house.
 
As far as the alpha thing, we are working on that. He doesnt demand food, he earns it. He doesnt expect attention, he earns it. He doesnt tell me when to go outside, he earns it. He doesnt walk back into the house without sitting/staying(as I'm inside the opened door pulling on the leash) until I LET him inside.Treats-he works for them. He knows sit, down, and stay at the moment although he does, and I admit, still get up without being released.
 
I'm not the person who goes and buys  GSD(german shepard dog),  never trains, it and then asks why he mauled some kid who only ran into the back yard to retrieve the baseball he and his friends hit into the yard. I knew full well what I was up against, but I was asking if anyone knew helpful tips other than convincing my neighbors and friends to walk into my house throwing treats everywhere.I will obviously ask them to do so, but I know that it can't be the only way to make him more accepting of people once I've accepted them.

Oh and shep, the second comment on this board is me posting an attachment of a picture of him after he donated blood. He was 9 months old?

I'm not terribly familiar with the breed, and I can't tell you honestly if this would be a good idea or not for your situation, but it's just a thought... someone else had brought up Shutzhund training on another thread, and maybe this is something you might want to consider.  If your dog is otherwise well behaved but has very strong guard/attack dog tendancies, maybe you're better off channeling these tendencies in a controlled and productive way rather than trying to work against it.  But I'd get the opinion of someone very familiar with both the breed and Shutzhund before exploring this route.

Oh he sure is a BEAUTY!!! Obviously I am a fan of bully, mastiff, big dog types! It sounds like you have no false perceptions of the breed of your dog and know you are in for a long ride. I hope you get a chance to google "NILF program" and take into account the prodecures because it has helped me a great deal and I think you can benefit from it as well. A great book for you to read is The Othe End of The Leash. It helps you see that some of the ways we interact with our dogs gives them mixed messages or how they might improperly interpret our actions. Actions as simple as letting our dogs walk through a dorrway first, eating dinner first, getting on the couch without permission may not seem like such a big deal to US but in dog language it means something entirely different. Please keep us posted!

A couple of things I would suggest - as others have said, find a different behaviorist.  Getting one to come to your home can get expensive, but is the best idea.  However, I think a good behaviorist should be able to give you suggestions on how to deal with the problem without necessarily having to see it in action.  If you have to describe the situation as opposed to letting him/her view it, be very specific and descriptive.  
 
You have indicated that you don't necessarily want to just have people come over and toss treats to the dogs, but I have had some success with one of my dogs who is aggressive and has bitten people with the same technique.  It's a kind of classical conditioning -  not so much to train a specific behavior, but to try and influence the way the dog's brain responds to the presence of people in the house.  
 
Briefly, this is what I do - I muzzle Gandolf (like I said Gandolf has bitten people), and let him drag a leash.  A guest calmly sits on the couch in our front room and tosses loads of yummy treats on the ground - no requirement that he do anything like sit, stay, etc..  Again, you're not teaching a behavior, just trying to change the association.  Gandolf gets to eat the treats (he wears a muzzle he can eat and drink from), and we end the session.  And we do it over and over.  
 
You could also work on "no bark," and "leave it" commands.  That way he could "warn" you, you can acknowledge his warning and let him know that he can then "stand down" from his perceived duty to protect the house.  Do go slowly and methodically with this training - it's not something your dog will learn overnight.

It sounds like territorial/protective agression.  In Zeus's old age, he has become a bit  territorial.  People used to be able to come up in the yard easily, but not these days.  Thus far, the only thing I found for help is "Nothing in life is free."  The whole point, from what I gather, is to have the dog defer to you.  I have been using the NLIF and  it is helping.  If Zeus is having a barking frenzy at something weird like a skater passing by the fence, he calls off quite easily. Before, he didn't.  I call him off and remove him from the situation. I don't give him any corrections or anything, just in the house he goes.  So, this may help you a little. It won't totally solve your problems, just another tool for your arsenal.