Early Access to Mass Effect 3 Co-op Demo!:
The Mass Effect 3 pre-release demo in January 2012 will have both Single player and multiplayer sections, giving fans a taste of what’s to come on 3/6/12.
Be first to the front lines in the multiplayer section of the Mass Effect 3 demo! Redemption of the Online Pass for Battlefield 3 will unlock this early access. But rallying for war is just getting started – in late November / early December BioWare will announce other ways for fans to engage the enemy with their friends from day one!
http://masseffect.bioware.com/
Down there
EDIT: Actually just Early access to the MP Demo...