XPMCK is a music (expressed in MML) compiler kit targeted towards various video game systems. It currently supports the following systems:

Capcom Play System (VGM output only)
ColecoVision
Commodore 64
MSX (KSS output only)
Nintendo Gameboy / Gameboy Color
SEGA Master System
SEGA Game Gear
SEGA Genesis

Besides the compiler and its source code, the kit includes playback libraries for all supported systems, as well as examples and brief documentation.

Changes:

Added support for the fifth Konami SCC channel.
Added a command for writing directly to a memory address or port.
Added the ability to output compressed VGM files (VGZ).
Added an alternative GBC noise frequency table (selected with #GB-NOISE 1).
Modified the data sequences generated at octave changes to use less space.
Updated the manual.

Thanks to the author, mic, himself for the news via ICQ.

http://jiggawatt.org/muzak/xpmck/