The following is a compilation of accessibility guidelines from a variety of sources. If you know of others that should be included, please let Jim Allan (jimallan@tsbvi.edu) know.
Authoring Tool Accessibility Guidelines 1.0 For software developers, explains how to make a variety of authoring tools support the production of accessible Web content, and also how to make the software itself accessible.
User Agent Accessibility Guidelines 1.0 For software developers, explains how to make accessible browsers, multimedia players, and assistive technologies that interface with these.