I went and got some for a steal on eBay. Felt it was risky but got such a good discount on 'as new' ones it was worth the risk!
They are amazing! My first proper ANC pair and although people say they are not the best in that area they are pretty decent in an office environment.
I'm just going to copy and paste handy bits out of the manual here for my quick reference.
Connect to two devices at the same time
Would you like to listen to music on your computer, but still be ready for calls? When
you've paired your headset and connected it to your phone, you can switch the
multipoint feature on and connect your headset also to another compatible device,
such as a computer.
1 Make sure Bluetooth is switched on in both devices.
2 Make sure the headset is switched on, and press and hold for 2 seconds.
3 Press and hold the volume up key and to switch the multipoint feature on.
4 Pair the headset with the second device.
5 Switch the headset off.
6 Switch the headset back on, and the headset connects to both devices.
To disconnect, repeat steps 1-3.
Manual found here