From
Wikipedia:
QUOTE
External iSight
Windows XP and Vista will autodetect an external iSight camera as “1394 Desktop Video Camera”, but no specific iSight driver exists for Windows. Nevertheless, most Instant messaging clients are capable of using video from the camera and adjusting brightness and other settings (the image will appear to be overexposed until the settings are altered). Windows is not capable of receiving audio from iSight’s internal microphones, as no Windows driver exists.
Technology blog Gizmodo reported in July 2006 that a bounty was offered for a driver that would enable the external iSight's microphone to function on Windows XP. Users were asked to contribute funds that were to be won by the successful developer. The driver's source would then be open to the public for porting to future Windows versions. After waiting 5 months with no submissions, Gizmodo canceled the competition, returned all donations, sold the iSight and bought a MacBook Pro.
So it sounds like the answer is "sort of." BTW - I think there is a fairly healthy demand for these cams still - eBay's sold listings show prices from $60 to $195 CDN (the $195 one was brand new).