Confirmed: the Plantronics 590a bluetooth headset can in fact be used with Skype. But the included “universal adapter” doesn’t fit the bill, since it only transmits outbound audio from the PC. To get both audio and mic, you need a dongle. Don’t ask me how but after some fooling around I got it to work on Windows. A couple of key parts were to a) have the PIN code ready — it’s in the Plantronics manual — for “pairing”, and b) know to hit the “call” button on the headset when, after “connecting” through windows, you start to hear a ringing tone in the headphones. The headset works with my new iMac as well, and no dongle needed since the new Macs ship with Bluetooth. The trick with the Mac is to manually re-assign audio in and out to the bluetooth headset when you want to use it (both switch automatically in Windows when you “connect”).