accessibility

How do you really test for accessibility? I put Easter Seals 
www.easterseals.com and Easter Seals Project Action 
(www.projectaction.easterseals.com) both through the Bobbi test 
(http://bobby.watchfire.com/bobby/html/en/index.jsp) and they both 
failed - yet it says on their sites that they conform to W3 standards. 
Can you please tell me the best way to test this?

Thank you.

Kathy Rausch
Founder
Interactive Ink, Incorporated
475 E. Mound Street
Columbus, Ohio 43215
www.interactiveink.com
v. 614-732-0870
f. 614-221-7098

"real . smart . solutions"