Apple wouldn't let you do it, but WinandMac found an app called iBluetooth for jailbroken iPhones that will allow you to send and receive files over Bluetooth. Just like a real phone!
There's really not much else to it. You can shoot files to and from Bluetooth devices, like other Bluetooth-enabled phones that aren't iPhones. If that's the one feature you've been waiting for, well, get to jailbreaking. [Win and Mac]