iEatBrainz
iEatBrainz is a MusicBrainz.org client that works directly with your iTunes library. WTF am I talking about?? Basically it makes an acoustic signature of a song and compares that with a database online to help you correct all your ID3 tags on your MP3's and AAC's. I ran about 2000 mp3s through it that had either bad, incomplete, or no tags at all. 1500 came back fixed correctly! After you verify the tags the app will apply the changes directly to iTunes. The bad news is this app crashes, A LOT. I've been told the developer is adding better error handling, but dont do too many songs at once, because after it crashes you will have to do them again. All in all it has tons of potential and still works damn well when it's not crashing.
-CGP fo Life-