Android Central offers up tips on pairing bluetooth devices. I'll have to agree with their synopsis... it's pretty easy but not all phones and devices are created equal.
My first phone routinely had Bluetooth problems and my second phone (A Samsung Epic) would sometimes fail to negotiate A2DP. Restarting Bluetooth on the phone and reconnecting to the device would usually solve it.
Read more at www.androidcentral.com
Pairing a Bluetooth device with your phone is a relatively simple affair. These instructions were written using the Samsung Infuse 4G and Jawbone Icon, but the steps should be just about the same for any Android phone or tablet, and the instructions that came with your headset will fill in the rest of the details.