there is a button for this on the main menu, you will find servers under the custom tab..alot of the servers are on diff versions in the server browser so try to join one that has 18.104.22.168 in the title..
Along with new multiplayer modes Valve included full working code for split-screen capability.
It doesn't matter if your game is old or brand new. An entire Community is there and wants to play with you! The survivors must fight their way through levels, interspersed with safe houses that act as checkpoints, with the goal of reaching a rescue vehicle at the campaign's finale.
You don't have to worry if your friends are miles away! The gameplay is procedurally altered by an artificial intelligence engine dubbed the "Director" that monitors the players' performance and adjusts the scenario to provide a dynamic challenge.
The Games on Demand version supports English, French, Italian, German, Spanish, Potuguese, Japanese, Chinese.
New from Valve® — creators of Counter-Strike®, Half-Life®, Portal™ and Team Fortress® — Left 4 Dead™ 2 is a new game that casts up to four "Survivors" in an epic struggle against hordes of swarming zombies and terrifying "Boss Infected" mutants. The Games on Demand version supports English, French, Italian, German, Spanish, Potuguese, Japanese, Chinese.