This video shows Matthias Ringwald's BTstack, BTstack Mouse & BTstack Keyboard (all available at http://code.google.com/p/btstack/) in action on an iPhone 3G. It's amazing how far you can go with a phone that actually is a computer. The iPhone hardware is awesome, so is the UI and the sometimes almost anal love for the details Apple has put into getting things right. Unfortunately they seem to have lost grounds a bit with their latest Terms & Conditions (see http://fuckclause331.com/ for details).
Hardware used in the video: