I've recently seen a few reports in the Google Places forum I help moderate but I didn't know the problem was this wide-spread.
<a href="http://searchengineland.com/google-sent-20000-hacked-notification-messages-to-webmasters-today-118585">Google Sent 20,000+ Hacked Notification Messages To Webmasters Today</a>
Google?s head of the webspam team, Matt Cutts, announced on Twitter that they have sent out new message notifications to 20,000 web sites that are hacked.