Pitt Bulls are good dogs. First recommendation I would make is to find a Vet that you are Comfortable with, and go with his/her recommendations. When it comes to food I would recommend a good large breed puppy food, and keep him on it until a year old, and then switch to large breed regular dog food. There is really no need to get it through the Vet, if they recommend it. We currently feed ours Purina One,as I have our last few dogs. We currently have a 7 month on Lab/Pitt mix, he is a rescue dog, and you could not ask for a better puppy/dog, is is already at 75 pounds last Vet visit. They are highly intelligent but cam also be stubborn and hard to train. Pet Smart and Petco both offer training courses for them as well, which I highly recommend. They may not be the best, but are a good place to start for a new owner. Your Vet could also guide you in this matter.
Good luck and enjoy your new family member. They are wonderful, and will provide you with years of companionship.
"Why is it that children know how to forgive and forget...But adults forget how to forgive?"