Tedd Sperling from Australia has created an audio 'Captcha' tool, an accessible version of the security tools used on many websites that ask people to type in a displayed code (this is to prevent access by 'robot' spammer software). If you can't see the code though, you're stuffed.
The accessible system speaks the code out loud.
Sperling invites readers to test it at http://www.sperling.com/examples/captcha/ .
All new content on my restarted blog is here