Zina is a graphical interface to your MP3 collection, a personal jukebox, a Podcaster, and an MP3 streamer. It includes an optional Flash player, a tag editor, and can search the Web for album art and song lyrics. It can run alone, be embedded into an existing Web site, or be used as a module in Drupal, Joomla, and Wordpress.
SQL Tagger reads the tags of audio files from a directory, loads them into a temporary SQLite database, accepts SQL queries to modify this database, then saves any changes back to the audio files. It's useful for performing complex updates that would be difficult or tedious with conventional taggers. It's a complement to conventional taggers, not a replacement.
The Ultimate Live Music Audio Converter is an audio conversion tool specifically designed around the file formats used for live music trading. It currently supports conversion of SHN, FLAC, and WAV files to MP3 or Ogg. Advanced features include automatic tagging of files using the contents of a set-list file (MP3, Ogg, and FLAC only), upload of new files into Itunes Library, and scanning directories where new files are downloaded (manual or automatic).