Section 508 of the Rehabilitation Act was amended in 1998, and among its requirements was a charge that the U.S. Architectural and Transportation Barriers Compliance Board (Access Board) must develop standards for accessibility of electronic and information technology. The Access Board did so and published the standards in the Federal Register in December 2001. In addition to the role these standards play in guiding federal agencies toward compliance with Section 508, the Access Board standards are being mandated or used voluntarily by many other organizations outside of the federal government, including educational entities.
The Access Board standards are organized into six technology categories, covering a full spectrum of electronic and information technologies, including web content, computer hardware and software, multimedia, telecommunications, and self-contained, closed products such as copiers and information kiosks. Of these categories, the most widely publicized is web accessibility. The web itself is rich with tutorials designed to assist web developers in understanding the 508 standards for web accessibility. Two excellent examples are Jim Thatcher's 508 Web Accessibility course  and Web Accessibility in Mind (WebAIM) , an organization whose web site includes a variety of tutorials for all levels of expertise.
There are comparatively few tutorials covering the other categories within the Section 508 standards, i.e., the categories other than the web. On excellent resource was developed by the Access Board, the same group who developed the standards. Their Guide to the Section 508 Standards for Electronic and Information Technology  includes well-written explanations of all standards in each category, plus answers to common questions about each. It also includes numerous technical examples, all of which are written in easily understandable language. The Guide is an excellent resource for learning about all of the 508 standards, including but not limited to web accessibility.
-  Jim Thatcher's 508 Web Accessibility course
-  Web Accessibility in Mind (WebAIM)
-  Guide to the Section 508 Standards for Electronic and Information Technology