abcmidi is a library of programs to handle abc music notation files
Music composer's best friend to find scales, chords and generate music
Versatile algorithmic random music generation software written in Java
the sexy sysex librarian that Linux needs...
Leadsheet notation with auto-generated playback, improvisation advice
A free karaoke player for Linux and BSD
Powerfull ATL Based Library (for VB6) / Strong Class Relations
Very Powerfull Crossplatform Qt Based Music Note Editor[Still Planing]