According to Joystiq:
Aliens: Infestation, the long-gestating xenomorph game for the Nintendo DS, has been rated by the ESRB. The classification board describes the teen-rated title as an action game, in which "players run and jump through side-scrolling levels, they use rifles, pistols, flamethrowers, and explosives to kill enemy soldiers and aliens (i.e., 'xenomorphs')."
My first reaction is - This sounds quite a bit like the SNES/Genesis Alien 3 game. I may be in the minority here, but I recall actually really enjoying the Alien 3 game (far more than the movie) back in the day.
With any luck we'll know more about Aliens: Infestation soon!