Free tools for those, who design gov websites.
Constructing a new www.srtr.gov site, I found some very useful tools to satisfy all requirements of sections 508. After you wrote a code, please use these tools to check if your code satisfies section 508.
1. Fangs - the screen reader emulator
2. Exclusively helpful site with a lot of free tools Illinois Center for Information Technology and Web Accessibility
3. Powermapper section 508 Accessibility testing Tool
4. Tools on WebAim site