mp3cleanup is used to tidy up various aspects of MP3 files, including filenames, ID3 tags, path, m3u playlists, and bitrate. This is particularly useful for hardware MP3 players that sometimes have arbitrary limitations on the files they work (well) with. It can operate on single files or on all the files contained in a directory.
Seems to be one of the few id3tag tools to handle international characters properly
as a result, the iRiver H340 is happy with the tags it produces in conjuction with libiriverdb (http://freshmeat.net/projects/libiriverdb/).