I always thought that mp3's where safe, let me explain what happened.
I was dl-ing a mp3 by "Morphine" it was a track I never heard of and it had absolutely .Mp3 as extention
(I thought I had everything of morphine)
The dl is almost finished, then norton av pops up, warning! referring to the unfinished mp3, (at that stage a Phex mp3.dl file)
So I aborted the dl, and scanned the file, wich according to norton contained a virus and could not be repaired.
I deleted it a while ago so I am not quite shure wat virus it was, and I can't find it in the log anymore but when I wanted to report it, I got the message, it was well known and not necessary to report.

edit:
I haven't got a clue how this "mp3 virus" would get the chance to indeed do it's thing, but who would rename a virus to mp3 if it did not do anything?