The four multiplayer maps released in Aliens vs. Predator's Special Edition will be available to the general public as DLC beginning next Thursday, March 18. The Swarm Map Pack will run you $7.
The DLC delivers four maps, two for the game's competitive multiplayer and two for its cooperative modes. "Docks" and "Machine" are available for the six competitive modes (Deathmatch, Predator Hunt, Infestation, Species Deathmatch, Mixed Species Deathmatch and Domination).
"Outpost" and "Hive" pit the humans, working cooperatively, against Aliens in a survival match set in an abandoned colony overrun by Aliens, and then an Alien breeding ground, respectively.