Is the dog you're thinking of trained? If so, it will have to meet evaluation criteria/testing before registration/certification. Though registration is not a mandate - under the ADA - it can help things go much more smoothly.

The following links have some good info.:

http://www.usdoj.gov/crt/ada/svcanimb.htm

http://www.power2u.org/articles/selfhelp/dogs.html

http://www.deltasociety.org/TextOnly...AboutStep4.htm

http://neurotalk.psychcentral.com/showthread.php?t=7204