This links should be helpful to anyone interested in learn about Accessibility.
- The Beginner's Guide to Accessibility
- Tips for Getting Started Writing for Web Accessibility
- Easy Checks - A First Review of Web Accessibility
- Start Building Accessible Web Applications Today (Videos)
- Live Accessibility Audit – Smashing Conf Toronto (Videos)
- Accessibility for Everyone by Laura Kelbag (Book)
Also, I recommend to follow these amazing people in Twitter: