It looks like someone posted about it on Norton's forums:
http://community.norton.com/t5/Norto...on/td-p/224672
If you use Norton, then you might want to keep an eye on that thread.
And here is a screenshot from someone talking on Google forums about a similar attack:
http://i117.photobucket.com/albums/o.../Capture-1.jpg
Is that the kind of popup you get?