I have Windows 7 x64 and it cannot find a driver for my Plantronics 520 bluetooth headset. I found the forums and this related thread
through Google. That thread links to an ASUS driver. I am downloading it because as far as I know bluetooth audio is an open standard. However that makes it a little bizarre for Windows not to be able to install the driver automatically.
I'll come back to tell you if I have any luck with the driver mentioned in that other thread. Plantronics don't provide any drivers on their website.