If you have a GMail account, log in and check your filters to make sure nothing suspicious is there:
> When logged into GMail, click on the ’settings’ tab in the upper right of the screen. Then check both the ‘Filters’ and the ‘Forwarding and POP’ sections.
Details here -- there's a vulnerability (apparently now fixed) that let people arbitrarily add filtering/forwarding rules to your mailbox. The author of the linked post had his website registration transferred to a domain thief that way.