On March 19th, Microsoft and Bungie announced that the next wave of downloadable content for Halo 3 will be coming soon.  Available on April 15th, this new map pack can be downloaded off of Xbox Live for 800 Microsoft points.  This new pack will include 3 new maps that will add to the multi-player experience. 

The two new maps that have been announced are:

Ghost Town - a maze of narrow passages and dangerous ruins outside the once-prosperous city of Voi. Collapsed ceilings and shell-battered buildings provide both valuable cover and deadly traps, as catwalks and stairways take the fight from claustrophobic ground combat to dizzying rooftop battles. This map ideal for Team Slayer games and smaller objective types.

Avalanche - this map is a tribute to "Sidewinder", a fan favorite.  The map is a massive, vehicle-oriented map with all new interiors, exteriors, and vehicle variants.

The third map is yet to be announced.  Stay tuned!