I think poohbear's mom wrote a great article on this matter as I experienced a similar situation with my pooch. lots of socializing and TLC are recommended as well as taking him to puppy school to socialize with other dogs in his age range and their owners in a controlled enviroment.
my pooch still growled at the vet :D, though they all admitted that he has greatly improved over the first visit where he wanted to ripe the vet's hand off .... sometimes i wonder if i'm raising a dog or an spoiled brat
