In a recent interview Doug Lombardi( Valve marketing vice president) revealed that this upcoming multiplayer co-operative survival horror FPS game will be coming to the PC and Xbox 360 worldwide in November 2008.

In the interview he was asked if they would have a free weekend-This would give player a chance to play the game  through Steam then have a chance to buy it- He said that "We’re kicking around a lot of ideas now and nothing’s final" but did say that there would “definitely” be a free weekend with a very possible demo.

Valve believes in quality and even though “the game is pretty much playable all the way through right now” they still want to fine tune the game to make sure that it is “approachable to players of all skills.” Doug also commented that Valve is interested in branching out into other genres such as MMOGs and family-friendly titles.

Valve Interview Part 2: Left 4 Dead Demo Potential, the Evolution of Steam, and More [ShackNews]