Tag&Rename

Tag&Rename is software from softpointer that allows unlimited access to updating the tags on your media files. The software gives you full screen edit capabilities and multi-file support to change groups of files with the same info. It can also be used to change tag format versions and to fix corrupted tags that might keep your music from playing in iTunes. (That's the reason I tried it in the first place).

http://www.softpointer.com/index.htm