Aren't there pictures floating on the net that show the HDMI output on the back of the 360?
The whole thing with the add-on is that it might cost more than the PS3 20GB (only $50 more), but Microsoft isn't forcing you to buy it to play games. If you want to play on a PS3, you have to get the BR player. If you want to play on the 360, you don't have to get the HD-DVD player.
And for a HD-DVD player, $200 is cheap. You are paying $400 for the 360, $200 for the HD-DVD player. Same price as the PS3.