So down in the forums we are trying to get a friendly L4D Dtoid Community tournament going.
http://www.destructoid.com/forum/showthread.php?t=11338&highlight=tourney

So far we have 5 1/2 teams. It's been slow moving and I have decided to promote it in the cblogs to see if anyone else is interested in getting in on the action. The more the merrier I always say.

Someone has mentioned why not the PC. Well thats because the person who started the thread said 360 first. I'm sure you can go out and start a PC one for Dtoid.
Also, it has been said that L4D isn't the kind of game that lends well to tournaments because of how much luck is involved with winning. I beg to differ. I think luck is part of the game but a larger part of the game is coordination with your fellow teammates.

If you want in, go into the thread and reply with your team added to the list and your team members. Or PM me and I'll do it for consistency.
Tomasz in the forum thread came up with some guidelines and rules for everything so if you go to the thread it will be explained in full.

Here are the teams so far:

Team 1
1 TheWolfParade (Tomasz)
2 KILL THE MUSIC
3 wasabiSABI420
4 QuixoticJacobit

Team 2
1 blehman
2 Zeke7hePlumber
3 CLIMAXone (a.k.a. unstoppablejuggernaut)
4 ProfPew

Team 3
1 Roshey
2 falinter (zoey!)
3 pezking6983 (louis)
4 Entranger

Team 4
1 ColMagoo
2 ColMagoo (1)
3 Arctic Fox18
4 Sing Sang Sung

Team 5
1 backflip10019
2 DJP3DRO
3 NegFactor
4 Maxpower

Team 6
1 Dok Industrial
2 Origim
3 Mxy (but he can only play 11-12pmish so that will be something to work out)
4 ?