Summer let me know about this slick deal for a super tiny USB Bluetooth adapter for $3.98 shipped at DealExtreme! This dongle supports the Microsoft stack in XP & Vista so this should work with desktop manager. Its based on an older BlueSoleil CSR chipset which is supposedly pretty good. Sadly I cannot recommend this based on experience since I do not have one so let me know if you pick one up and it works!
Nice find Summer!