Here you find Daniel Taupin's MusiXTeX a TeX-based system to typeset music.
Older versions are available too as zip-files named musixtex.nnn.
If you want to use these diff-files you may have to rename them either when ftp'ing them or when unzip'ing them. Mac-users may need this file. One of these are needed only for TeX-systems which do not generated the fonts on the fly.