Coping With Canine Aggression

I have a three year old Red nosed pit bull that is something else. We got him fixed on the opinion of a dog trainer, they said it would keep him from being aggressive, but it has somewhat kept him from being aggressive. The problem that I have is that he does not like any other dog but my little dog. We may have to move and I am afraid of what is going to happen to my dog. I really love him, he is part of our family. Almost every city here in my state has outlawed pits. What are we supposed to do. I just wished he was not so mean to other dogs that he could get along with them. I feel that it is a territoral thing with him, but I do not know what to do so I am hoping someone has a suggestion that is not going to cost me bundles. Thanks