With this software your macbook trackpad or magic trackpad works as midi-controller.
The trackpad is divided in 4 sections, each one sends coordinates of a touch.
The “MIDI Learn” window can help to map controller in Ableton Live etc.
Works under Mac OS 10.5+
Made with Max 6 and fingerpinger object.
Source (max patch, messy):Trackpad4.beta1.source