BeaTunes is a useful companion to iTunes that can detect and resolve many common library problems, create well-matched playlists, import lyrics, and more.
Launch the program and it will immediately import your iTunes library, and go hunting for issues. These might include multiple spellings for the same artist (REM or R.E.M., say), duplicate files, misspelled album names, rarely used genres, mismatched release dates (songs belonging to the same album with different release years), and more. The trial version will only display these errors, but purchase a licence and you'll be able to fix them in a click or two.
If you have files with ambiguous names, like 01-track.mp3, then beaTunes can use its MusicIP fingerprinting technology to retrieve the track name, artist, album and more (as long as they're not DRM-protected). It'll then give your files more meaningful names, and set their tags, too.
The program is also able to analyse the beats per minute and tonal key of your songs, using this and other information to create playlists of songs that work well together. Or, if you have plenty of playlists already, then beaTunes will sort them so that, wherever possible, the best-matched songs always follow each other.
And beaTunes delivers plenty of other useful features, including options to import song lyrics from Lyricsfly, organise your library with del.icio.us-like tags, or create blog entries at blogger.com with your favourite songs or playlists.