WCAG stands for Web Content Accessibility Guidelines. It is a set of guidelines produced by the WAI (Web Accessibility Initiative), a working group of the W3C (World Wide Web consortium), a body dedicated to establishing standards on the Internet. The current version of is WCAG 1.0. WCAG 1.0 outlines many guidelines for web designers to use to ensure the maximum accessibility of a web site. Currently, WCAG 1.0 divides up guidelines into various levels of priority - priority 1, 2, and 3, with 1 being the most important. LecShare Pro creates output which adheres to priorities 1 and 2 and much of priority 3. (Some of the aspects of priority 3 can not be checked automatically by computers and require users to check for specific content.)
WCAG is not enforceable by law like Section 508, but it's guidelines are highly recommended when designing web sites. WCAG covers all of the areas of Section 508 and goes into more depth and even goes beyond Section 508 requirements.
Read more about Section 508