When not being used to control 15-ton grapples and Airsoft guns, they can also be synced with iPhones, and used for input — made possible with BTstack 0.1. The software essentially “creates device connections using the L2CAP protocol.” Video after the break.
The code is currently aimed at jailbroken devices only. It supplies a Bluetooth daemon (BTdaemon) that you access from your apps.
[via TUAW]