Pulling on leash when sees another dog

You should eb taking him to a obedaince class so they can help you help him. Not only is is great fo tthat but he will get to socialize with other dogs so they dont seem so taboo to him. If dogs dont get properly sociallized they can develop leash aggression and that is pretty ahrd to break. At this point in  his life he is happy and wants to play but after so many of these instances he is going to grow frusterated and then pissed. When Rory was going through this as a pup I noticed that letting ehr touch noses and say Hi calmed it a little bit but ONLY if the other dog handler seemed aggreable.A obedaince class will help him understand you are the alpha and is great bindign time for the two of you.
In the meantime carry some treats, when you see another dog approaching keep his attention on you with the treats, make him sit and be calm and dont talk to him in condoling tones or he'll think his behavior is ok. Obviously I'm not suggesting being mean but a firm "sit" and "stay" will tell him his behavior is not ok. A precentage of this typical puppy behavior and excitement but a firm obedaince class is the trick to it not turning into a major adult issue!

Does he have appropriate opportunities to play with other dogs? do you ever let him interact with dogs while he is on leash? I have a strict "no interacting, not even sniffing at other dogs or people while you are on leash". It prevents so many problems from developing.
I think you need to add an extra step to your leash-walking program: practice doing a lot of sudden turns. Call his name, and turn sharply, and reward for him coming with you on a loose leash. Do this at random, often.

We did do a "puppy class" with him. He loved the dog socialization time. We learned sit, down, and the basics but we were not overly impressed with the class. We should probably look into another class somewhere else. The instructor told us that the next class would be a lot of review. We may be foolish, but it seems like once you get the jist of the training technique it just takes lots of practice. That is another reason we did not sign up for the next class.

His favorite thing to do is wrestle around with other dogs. He could do that all day. He has never been aggressive towards humans or dogs; he is very friendly and curious. When he sees people across the street doing something he wants to sit and watch them even if we are on a walk. Another problem is sometimes with people walking down the block toward us he lays on the grass and waits for them to get close and then jumps up at them. I try to encourage him to keep walking so this does not happen but he just lays down where I would have to drag him to keep going. Then while he is laying down I step on his leash so when the person passes he can not jump up. We have a VERY hard time getting his attention when there are distractions even with treats. How should we practice this?

He is a pretty mellow good natured puppy it is just the jumping up and pulling that we have problems with. He is totally going through the adolescent stage right now too. Challenging who is the alpha.

I would saturate your dog with everything and everyone, give him plenty of excersise (as much as you can)  pratice on a loose lesh and if he see's a dog find a command that he will responde to, such as his name!  don't fight with him (or you are respect his wishes)  walk the other way or turn direction...

He's young. He still has to mature and learn some self-control. He must learn that there are appropriate and inappropriate times for him to play with other dogs. When you're walking him, be alert. As soon as you see another dog coming toward you, before your dog gets very aroused, have focus on you. Getting him to sit and wait may be a little challenging at his age and level of playfulness, but try something more exciting like trotting after you in a different direction. Even for treat motivated dogs, treats are often not very exciting outdoors on walks. You have to work with the rewards the situation has to offer - like forward progress! You might do well do get in some more mentally and physically challenging exercise than just leash-walking, like running around or swimming.
 
ETA - what I forgot to write, though, is keep your expectations realistic. Even though you want to work diligently to prevent this becoming a lifelong habit, it's also fine to recognize your dog is a puppy and isn't going to be perfectly behaved... expect good days and bad days and just keep at it. [sm=wink2.gif]