This is the home of defMON — a music editor for the Commodore 64. There is no official support for the program, but at least there is this wiki that allows defMON operators to collaborate to accumulate information and documentation.
Contributions to the site are encouraged. Just register and go ahead!
If you want to stay up to date with changes on this wiki, subscribe to the RSS feed.
A MIDI/DIN/LSDj/Nanoloop/etc hardware sync interface for defMON is now available for sale from Scannerboy at chipmusic.org.