From the preview over at Planetquake4:
Other features include in game voice chat, absolute Linux support (though may not be 100% done at the time of shipping), Punkbuster for anti-cheating, and stopwatch mode for tournament play.
Sweet! Enemy Territory: Quake Wars will run on the Doom3 engine, and is being developed by Splash Damage, who did the original Enemy Territory. Quake Wars pits Strogg vs. Humans as the Strogg invades Earth, and will the two sides will have entirely different classes and vehicles.
I’ve been talking this game up for a while, and I’m very excited they officially announced Linux support.