Check out BioWare Pulse Episode 46 that highlights the newly announced multiplayer for Mass Effect 3 coming in March.
In Mass Effect 3, an ancient alien race known only as Reapers, has launched an all-out invasion of the galaxy, leaving nothing but a trail of destruction in their wake. Earth has been taken, the galaxy is on the verge of total annihilation, and you are the only one who can stop them. The price of failure is extinction.