ALSA
There are currently two concurring projects:
- Complete ALSA support (audio signals and MIDI): http://code.haskell.org/alsa/
- ALSA sequencer support (aka MIDI): http://open-projects.net/~shahn/index.php?seite=code, http://hackage.haskell.org/cgi-bin/hackage-scripts/package/alsa-midi, http://darcs.haskell.org/alsa-midi/