Audio CAPTCHA review request

Hi gang: If you people would be so kind as to review this: http://sperling.com/examples/captcha/ and tell me what you think (ease of use, if it works, security, etc.), I would appreciate it. The point is to be able to get to the "Congratulations" page by hearing and entering the key. If you can get there some other way or defeat the process, I sure would like to know about it. I've tested this with a couple of dozen blind users and they find no problems with it. Now, I'll like to test it for the sighted. It's mixture of a several languages, but there is php in it, so I guess it's on topic. Cheers, tedd -- ------- http://sperling.com http://ancientstones.com http://earthstones.com