This site may be of some help:
DogFriendly.com PetRelocation.com seems to have the same information. Apparently basic requirement for US has to do with rabies vaccination.
It does depend a bit upon where you're going and when though, keep in mind that some of the States are quite warm already and basics of pet travel depend upon whether your dog will be traveling in cabin vs as cargo on your flight vs shipped "as cargo" on it's own. As example, I think it may already be too hot in Florida (particularly south Florida) if your dog is traveling as cargo with you, as it will be too hot on the flight deck during loading and unloading.