some months ago i was royally ed off the customer support from terratec for they told me, there would never be any drivers for w2k. accidentally i found out that the terracam usb is technically nearly identical to the webcam2 usb from creative, and they've got w2k beta drivers that work quite fine with the terracam. you can't access the settings dialog, but at least you can capture pictures via the twain driver.
http://www.europe.creative.com/support/drivers/product.asp?prod=25