There is no bluetooth native to the 7921. Also as you may know, bluetooth also operates in the 2.4 GHz space, so could effect quality if using 802.11b/g.
There are some companies that make an adapter from 2.5mm headset jack to Bluetooth adapter, but have only seen the 2 band / 3 conductor type (non-Nokia compatible).
Only wired headsets from the URL provided above are supported on the 7921. There are also options from Jabra www.jabra.com as well.
