I've recently taken the plunge and have installed Fedora 15 KDE x64 after previously using Windows 7. I've done some googling and have discovered there is no out of the box support. I've tried some of the fixes I found on the net, but they don't seem to have worked, as I'm still unable to play MP3s.
Another issue I've found (and suspect it's related to Fedora's inability to play MP3s) is that when copying files from Fedora to my MP3 player, the songs don't play right. Instead, most tracks have not been transferred (despite the files appearing on the PC) and those that do have been mis-mashed together - tracks have been stuck together, with it randomly changing song halfway through the track but not changing track name number artist album etc etc.