Some tutorials for Web Sites Accessibility:
1. WebAim Introduction to Web Accessibility
http://www.webaim.org/intro/intro
2. SitePoint - Introduction To Accessible Web Design, by Nigel Peck
http://www.sitepoint.com/article/952
3. SitePoint - Do-It-Yourself Accessibility by Nicky Danino
http://www.sitepoint.com/article/744
4. Information Technology Technical Assistance and Training Center
http://www.ittatc.org/training/webcourse/ (Free registration required)
5. HiSoftwareŽ Understanding Accessibility
http://www.hisoftware.com/uaen/WebHelp/uaen.htm
6. Web Accessibility Learning Modules
http://www.csufresno.edu/webaccess/learningmodules/
7. Dive Into Accessibility
http://diveintoaccessibility.org/
8. Designing Universally Accessible WWW Resources for People with Disabilities
http://cita.rehab.uiuc.edu/courses/2002-02-REHAB711NC/
9. Making Your Site Accessible
http://uaweb.arizona.edu/styleguide/accessible.shtml
10. W3C Example for Checkpoint
http://www.w3.org/WAI/wcag-curric/sam1-0.htm
11. JimThatcher.com - U.S Section 508
http://www.jimthatcher.com/webcourse1.htm