Don't know if you guys have seen this yet, but Newegg is putting together an online tourney with $25,000 in prizes. Not sure if it's only open to US residents or not. Some of the games include CS 1.6, Gears 2, Left 4 Dead, Dawn of War 2, and a couple others.
See here for more info or to sign up. It is free to join the tournament.
Newegg Wanfest
If we can get some folks together I would be interested in the L4D 4v4. Let me know if anyone's game.