Section 508
US governmental guidelines for producing electronic information and technologies accessible to people with disabilities. The laws, a 1998 amendment to the Rehabilitation Act, apply to all federal agencies and serve as an excellent guide for all web developers. Section 508 deals more specifically with IT issues and goes beyond those guidelines previously suggested by ADA.

Web Accessibility Initiative
WAI, in coordination with organizations around the world, pursues web accessibility through five primary areas of work: technology, guidelines, tools, education and outreach, and research and development.

Accessibility in Macromedia Dreamweaver MX
A useful overview of accessibility options introduced in Dreamweaver MX. This new version of Dreamweaver offers many improvements for users of assistive technologies, as well as for individuals seeking to create accessible web content and web applications.

WebAIM
WebAIM provides extensive resources and training for expanding the Web's potential for people with disabilities. Resources provided include not only HTML, but also SMIL, RealMedia, QuickTime, Windows Media, and other multimedia technologies.

Six Principles of Accessible Web Design
An excellent overview of accessibility issues, broken down into six basic principles. Based on the full WAI guidelines and published by the the HTML Writer's Guild.

IBM Web Accessibility Checklist
A convenient checklist of 16 important accessibility checks when creating web pages and/or web applications.