Valve announced today that Left 4 Dead is available for pre-purchase via Steam. The survival horror game has single player, multiplayer and co-operative gameplay modes. Those who pre-purchase via Steam will save 10% off the regular price.

"With just over four weeks until launch, Left 4 Dead is showing every sign of topping The Orange Box on both the PC and Xbox 360, at retail as well as on Steam," said Doug Lombardi, VP of marketing at Valve. "Our pre-sell numbers at retail have jumped to over 65% greater than Orange Box at the same proximity to launch, and we're seeing tremendous enthusiasm for the product in what promises to be another great year for gaming on both platforms."

Left 4 Dead will release on PC and Xbox 360 on November 18.