Old news actually
http://apple.slashdot.org/article.pl...id=126&tid=172
No one has actually released anything that can cause harm and you would have to create an archive of the MP3 for it to survive across the internet or the resource folk would be stripped off removing the threat. So just sending someone a MP3 file will not do it.
It is basically a very low threat, but someone could use the mechanism to do harm if they had access to a local LAN. Took 3 years for someone to come up with this and it is expected to be taken care of in the next update from Apple.