You can pair your Windows Phone 7 with a variety of Bluetooth devices like other phone, headsets, speakers, car-sets, etc.

To do so under Settings, tap Bluetooth and move the slider to ON. Make sure that the other device is also turned on and if it requires you to enter a PIN, please do so.
However you may find that you are unable to pair your WP7 with another Bluetooth device or accessory.
Windows Phone 7 supports Bluetooth 2.1 + EDR which is an enhanced version of Bluetooth. It therefore supports the following Bluetooth user profiles only:
- Advanced Audio Distribution Profile (A2DP 1.2)
- Audio/Video Remote Control Profile (AVRCP 1.0)
- Hands Free Profile (HFP 1.5)
- Headset Profile (HSP 1.1)
- Phone Book Access Profile (PBAP 1.0)
Certain Bluetooth devices may not fully conform to industry-standard Bluetooth protocols and therefore your Windows Phone may not be able to connect to certain Bluetooth accessories or devices.
