Here are a few sites that you may find of use:

PetTravel.com - passport, airline, USDA information and more for the national and international pet traveler.

Pet Services Directory
This is an exclusive USA Pet Services Directory to help internet shoppers locate pet professionals that provide pet services and pet products in the continental United States. Just Follow the links to the geographic area you want to explore.
http://www.pet-services.org

CL - the UK online shopping directory

Dogfriendly