Puppy Training Virginia

How can I find a good dog trainer?
Hello, my friend lives in southern Virginia, and is looking for a good dog trainer come help with his dog (learning to walk on a leash, potty train, etc.) It has orthopedic problems and therefore want to work with a coach. How to find a reputable trainer. Is there a national association? Do you need some kind of qualification or you can say that working with dogs. She wants to use positive methods – no choke chains or shock collars. Thank you!
This list http://www.trulydogfriendly.com/blog/?page_id=4 trainers who are dedicated to using positive reinforcement methods and dogs.
English Bulldog Puppy Training. Good Puppy.