Presumably to muffle the cries of their colicky fanbase over the abrupt announcement and impending release of "Left 4 Dead 2", Valve will be releasing a new campaign for the original game in September. However, unlike the last pack of DLC that included new multiplayer maps and an entirely new online mode, XBOX360 users are going to have to pony up the dough for the new "Crash Course" campaign.
While containing both Survival maps and a Co-operative Campaign, the primary goal of "Crash" is to deliver a complete Versus mode experience in just 30 minutes, resulting in a streamlined version of the game's existing Versus campaigns. A recharge timer for infected teammates has also been added, and item spawn behavior has changed for more balanced gameplay...
...Left 4 Dead: Crash Course is targeted for release in September and will be available free of charge on the PC and for 560 Gamer points on Xbox Live.
I tend to rush to get my hands on any "Left 4 Dead" content, but I'm already committed to buying the next game, so I'm not sure this is worth it. I don't think that Valve is to blame for the disparity between platforms, but it's still puzzling that I'm going to have to pay for essentially a third of the content I got for free a few months ago. The saga continues...
Source:
More Left 4 Dead DLC Announced