Be carefull with that dog.
My neighbor had one of those little chiuahas like the Taco Bell dog. I guy with a Pit was walking his dog on a leash and the thing just broke free and mauled the little chiuaha. It took all of a 2-3 seconds.
The guy claimed the Pit was social with kids and other dogs and had never attacked anything but rabiits and squirrels. He never thought it would attack another dog. He thought wrong.
I'm not saying you have a bad dog, just realize that you have a larger responability because of what your dog is capable of doing.