It's either this one:

http://www.youtube.com/watch?v=y4CyNvEfWoE&feature=related 
<http://www.youtube.com/watch?v=y4CyNvEfWoE&feature=related>

Or the Al Yankovic version:

http://www.youtube.com/watch?v=tigMpQ5j89s&feature=related 
<http://www.youtube.com/watch?v=tigMpQ5j89s&feature=related>

- Mark