SortSite - Accessibility Checker and Validator
SortSite checks sites against the W3C WCAG 1.0 and 2.0 accessibility standards, and compliance with Section 508 of the Rehabilitation Act.
These checks help find problems stopping disabled users from using a web site.
Reviews and Testimonials
SortSite is a very good testing tool. It will test all pages it finds on the site.University of Cambridge
This simple test ... gives much more useful data than just a screenshot. The "SortSite" test checks accessibility, broken links, browser code compatibility, search engine optimization and other usability issues...practicalecommerce.com