Downloadable content for Left 4 Dead has finally been released on Xbox
Live. It costs 560 Allards and includes a two chapter campaign that
picks up from our heroes at the end of the No Mercy campaign in the
full game. There are also ten new achievements, and the pack is
compatible with all of the Left 4 Dead modes (Co-op, Survival, Versus).
However, if you have the PC version of the game, you will be happy to
know that this DLC is completely free for you. Microsoft seems to be
completely against free DLC with the 360, and rumours are currently
circulating that they forced Valve to charge for it in order to not
show up other developers charging the odds for their (mostly)
disappointing add-on content.
http://www.xboxfocus.com/