How to enable and pair a Bluetooth device to your iPhone 3G.
1. Set your Bluetooth device to discoverable.
2. From the Home screen, select Settings.
3. Select General.
4. Select Bluetooth.
5. Set Bluetooth to On.
6. The iPhone starts searching for Bluetooth devices. It should show up on the screen where you can enter the PIN code. Enter the PIN (usually located in the manual). You should then be ready to use the Bluetooth device with your iPhone.