The World Wide Web was built with the objective of delivering content to all users, across heterogeneous systems and platforms. The idea worked for the most part, but we still have issues with the way browsers work - some sites require the use of a specific browser and, at times, developers create different versions of the pages for different web browsers. To help remedy the situation, the World Wide Web Consortium (W3C) came up with the Web Content Accessibility Guidelines (WCAG).
The WCAG 1.0 standard was published in May 1999. A draft version of WCAG 2.0 was created in January 2001, and the proposed version was formed in November 2008. WCAG 2.0 is expected to be published as a standard on 3rd December, 2008.
You can access the proposed WCAG 2.0 here. Also useful is the CSS techniques for the proposed WCAG 2.0 here.