How much would the dongle cost? Any link to it at http://www.bestbuy.ca http://www.futureshop.ca or http://www.tigerdirect.ca all are within 15 minutes of my house
You can capture any video via firewire.
I have no idea about the xbox, but from my DVR I can capture the video using a firewire cable and the Firewire SDK that it's free to download from website.