MidiO is an Audio Unit plugin that generates MIDI out for GarageBand software instrument tracks. It can be used to directly drive either external MIDI devices or standalone software synths. The plugin can NOT directly export MIDI tracks to disk.
What's new in this version:
Passes AU validation under 10.6. Can generate program and bank change messages.
This review was originally posted on VersionTracker.com. The author should be charging at least 10 bucks for this version. Works like a charm. If you own Garage Band and some external MIDI synths, you should have this tool.