Would you look at this: Electronic Arts' official store has added a listing for Mass Effect 3. There's even a description:
Earth is burning. Striking from beyond known space, a race of terrifying machines have begun their destruction of the human race. As Commander Shepard, an Alliance Marine, your only hope for saving mankind is to rally the civilizations of the galaxy and launch one final mission to take back the Earth.
Sounds serious. Mass Effect 3 is rumored to be revealed at the Spike Video Game Awards tomorrow, and this (likely accidental) listing basically seals the deal.