Some researchers from the Media Computing Group at RWTH Aachen University (Germany) have been working on a Cocoa Multi-Touch Framework for Mac OS X. Being part of a group conducting research in Media Computing and Human-Computer Interaction (HCI) aiming to bring next generation graphical user interface, they are currently working on the first public release and will soon provide an early version of the framework. A demo of the Cocoa Multi-Touch Framework is available on YouTube:
As mentioned by the developers, the beauty of the system is that you can develop and test your multi-touch application on your standard desktop Mac, using your iPhone as multi-touch