MTV Multiplayer has word from Jeff Gardiner of Bethesda Softworks on new weapons and a new perk to be added to Fallout 3 in the upcoming Mothership Zeta DLC for the post-apocalyptic action/RPG. The mission-specific perk is called Xenotech Expert. Word is: "It increases the damage you do with alien weapons, including the Alien Blaster if the player had found that in the wasteland." And here's what Jeff told them about new weapons:

Mothership Zeta is full of the most high tech weaponry in the game. It includes a Shock Baton for melee fighters, multiple new firearms including an Alien Atomizer, a pistol, and the Alien Disintegrator, a new rifle. There's also a new grenade type, a Cryo Grenade, which freezes enemies for a short period of time. On top of that there are new unique weapons, and a new heavy weapon.