Gents, I've done a lot of research on BT (unfortunately) mainly because I wanted to develop some BT apps for WinXP. Well, here's the prob: there's no built-in support for the BT profiles (headset, filetransfer, image transfer, etc., etc.) into Windows. Microsoft has some real barebones drivers. There's WIDCOMM that has full featured software (and drivers) that do all the neat stuff that people expect from BT. You have to be careful when you buy a BT adaptor. Get an adaptor that uses the WIDCOMM software and you'll be fine. I've got two adaptors: a Belkin USB adaptor that uses the WIDCOMM software and the Sony VAIO BT USB adaptor that uses the Microsoft drivers. The thing is that if Sony wanted to they could write full featured software because the API is there, but they only support the bare minimum (HID, file transfer, dial-up, and some others, not headset for instance) for some reason. Anyways, pretty much every BT adaptor will support HID (keyboards and mice). I use the Microsoft BT mouse with both the Belkin and Sony adaptors fine. Also, note that Microsoft's BT adaptor that comes with the BT mouse only supports HID. I use the Sony adaptor for BT software development because WIDCOMM doesn't make their API available (it costs money).