I'll fess up here...I'm a design engineer at Motorola Brum and specialise in "blueteeth" products and even I don't wear the poxy headset things. They look nasty, you look silly and you deserve to be laughed at of you wear it on the bike and then faff around trying to take a call and rear end a white van in the process
Having said that...fab technology...get some Motorola S9's...now they are good...specially seeing as they are my design lol
http://direct.motorola.com/ens/s9/Headset_Home.asp
I've done a BT integrated Bell cycling helmet and a wooly Burton snowboarding hat, I'll try and post some pictures if I can dig them out. The best bit of kit so far is the snowboarding jacket with wireless everything...I was still crap when I went snowboarding though lol