Matthias Ringwald, of iPhone Bluetooth fame, has just released BTstack 0.1 for iPhone. This video demonstrates his group's technology in action, as an iPhone syncs with a WiiMote and then uses the WiiMote for input. Although the system does not yet have OBEX, it is, as Ringwald writes, "better than Apple's nothing."
I haven't had a chance to give the software a spin yet (you can download the source from Google Code) but I'm looking forward to playing. BTstack creates device connections using the L2CAP protocol. The code is currently aimed at jailbroken devices only. It supplies a Bluetooth daemon (
BTdaemon) that you access from your apps. Given that the release is still only at version 0.1, expect a certain degree of instability and a lot of further development potential.