I read this article on Digg but it needs to be spread as far and wide as possible. There was apparently a GMail exploit in the wild that let someone hijack your email. This guy lost his domain over it!
WARNING: Google's GMAIL Security Failure Leaves My Business Sabotaged
The very short version is that you should check your GMail filters NOW to see if you have any stray entries in there.
UPDATE: Enough people helped to spread the word and contacted GoDaddy.com that they got involved and David got his domain back! Details here.