One of the more interesting features that was announced during the preview of iPhone OS 3.0 was the GameKit framework.
The video above is just a simple demo I wrote a few months ago with a beta version of GameKit and the cocos2d-iPhone framework. The two devices discover one another over Bluetooth, coordinate the client / server relationship, and begin play. There’s currently no scoring, and my protocol implementation is highly inefficient.
While the framework provides many neat features, I was most attracted to the zero-configuration P2P over Bluetooth. Multiplayer applications were previously only possible using Bonjour over WiFi, or some roll-your-own solution over the cell network. These methods provide a significant barrier of entry when you consider that the most popular games on this platform are the pick-up-and-play / get-in-get-out kind, with a typical play session lasting five minutes or less. If I have to fiddle with my network options in order to play an ultra-casual game with you, I most likely won’t.
The bad news? Bluetooth P2P is only available on iPhone 3G and 3Gs, and iPod Touch 2G.