Make sure that in the File Exchange control panel, all mp3's (including MP3, in caps) are keyed to iTunes. If for some reason this still gets overridden, get a little freeware app from versiontracker.com called "iTunes Associator". This automatically changes the file type and creator to iTunes. You can do this yourself, of course, with ResEdit, Norton FastFind, or any other program that can change this in the resource fork.