It sounds like the title of a really shitty sci-fi movie you'd catch late at night on cable... Attack Of The MP3 Virus. Apparently, there is a new worm, called W32.Deletemusic, that rummages through your PC and gobbles up all of your MP3s. This little bugger also attacks any external drives you might have, even memory cards are at risk.
We searched around for more info on this virus, and according to Symantec, it was originally discovered on July 30. It is considered a low threat, but you might want to think twice about plugging in somebody else's flash drive... think of it as safe sex for MP3s. This only affects computers running Windows 2000, 98, 95, Vista and XP, so at least Mac users are safe... for now.
If you haven't done so lately, it might not be a bad idea to back up your precious MP3 collection. Get yourself a nice external hard drive or burn the files to DVD... just in case!