Anith Gopal

The iPhone/iPod 3.0 OS allows third-party applications to utilize the device’s Bluetooth capabilities for two-player games. The first (and only) application I had that supported this in an update was Flight Control, and since then, whenever my wife and I are on a train, we occupy our time playing this. The huge advantage of multiplayer Bluetooth compared with Wi-Fi is that you just need the two devices, no Wi-Fi access points or Internet connectivity is required

Excerpt from: 
27 Bluetooth-enabled Multiplayer iPhone Games