The following tools can help make your job of ensuring accessibility easier:

• Fangs - Screen reader emulator that allows you to read how a page would be represented audibly to a screen reader user
• WAVE Toolbar - a browser toolbar that automatically scans for errors on the page
• Link checker - WTS runs a service that can automatically check all your site's links every month and email a report to you
• ConvertDoc - email your image-based PDF documents to convertdoc@umontana.edu and it will automatically return an OCR version of the PDF

Additionally, the W3C maintains a list of accessibility tools that you can filter by license and standard.