I've set up an AIM group chat room for back channel conversation etc... during Merlot 2003.
In any AIM client (like iChat or whatever floats your boat) just head to chat room "Merlot2003"
I'll also have a Hydra document open for sharing notes on the LAN as I take them (if I take them...)
UPDATE Here's the URL for joining the Hydra document if you're not on the LAN.
UPDATE 2: Wireless coverage turned out to be spectacularly spotty, at times making WWDC2003 look absolutely flawless. Oh, well...