ARgh!

if you buy the game new:

"Named "The Cerberus Network," the program is free to all of those who buy a copy of Mass Effect 2 new at retail or via digital distribution."

"Once connected to Cerberus, be it through a code or paid access, players will have free access to a DLC pack containing a new character, new missions, and new items. That launch-day pack is to be followed by a further free pack containing a new vehicle along with missions and items at an unspecified later date."