Info I'll stick here in case I can't find it again, thanks to Murphy...

http://home.brisnet.org.au/~mlevoi/midi.html

GS - XG - GM MIDI Software and Visual Basic Code
including
Thanks to the extraordinary generosity of James Shields and Zane Thomas, the Mabry MIDI Pack source code has now been put into the public domain! Specifically, you can find the complete source code for the VBX, OCX16 and OCX32 versions of:

MIDIFILE
and
MIDIIO