Microsoft has confirmed the DLC for Valve's Left 4 Dead will hit the Xbox 360 this April 21st, and most likely the same for PC gamers.
The DLC packs includes a new survival mode where players have to hold out against hordes of undead, and enters two campaigns into Versus mode; Dead Air and Death Toll.
Valve themselves have said previously that the DLC would most likely hit both platforms simultaneously so hopefully April 21st will bring much undead joy to desktops too.
Source: CVG