Mutabor is a program that allows you to perform and compose microtonal music using a normal MIDI keybord and normal MIDI equipment. Its powerful description language is intended to allow permanent retunings and complex tuning logic. One application is just tuning. Mutabor has been used for this purpose to make available all pitches that can be reached by stacking perfect thirds and perfect fifths. The stable version 3.0x is available in German only and runs under Windows and Wine. The unstable branch can be accessed via CVS (but build bugs should be expected) or downloaded from the Berlios developer site.
Guayadeque is a music player that aims to be easy to use and fast even for huge music collections. It allows you to automatically or manually download covers, easily organize the music library, edit the ratings of the tracks, add labels to the artists, albums, and tracks, listen to shoutcast radios, download lyrics, show artist information based on last.fm content, and more. It includes a simple, built-in tag editor with picture support.