I'm not sure how, but I'll double check my AppleTV later. Bluetooth bandwidth I think would have a hard time coping with what would be needed for video. Under the releases prior to the most recent, the AppleTV never exposed any Bluetooth functions to the user, including the necessary pairing/discoverable toggles.

Bluetooth and AppleTV appears to be a worthless google search, due to the echo chamber effect of the rumor of Bluetooth keyboard support coming in iOS5 for ATV. No solid confirmations at a quick glance now that the update is out.

And good to know about the keynote remote working iOS to iOS.