iArt – Automatically get album art and lyrics for your iTunes / iPod!
Forget about iTunes Art Importer. If you can afford $10 this is an awesome program. It updates your album art and lyrics! It will also automatically create playlists of songs that have no art, multiple art, or no lyric, so you can go back and manually fix the files that it can’t find art or lyrics for.
Definitely check it out.