Web Content Accessibility Guidelines (WCAG) 2.0 [1] covers a wide range of recommendations for making web content more accessible. Only the official WCAG 2.0 can be used to verify conformance with the guidelines.

Understanding WCAG 2.0 [2] is a guide to understanding and implementing Web Content Accessibility Guidelines 2.0

WebAIM WCAG 2.0 Checklist [3] is provided by Utah State University and it presents their recommendations for implementing accessibility principles and techniques for those seeking WCAG conformance.