Last month Mass Effect 3 got a bit of co-op DLC, which was released at no cost. But since then we haven't heard much about the game, other than the fact Bioware is working on another piece of free DLC to "enhance the ending" - which was the cause of much controversy when the game was launched. An internet leak, as reliable as those always are, may point out some more information about the free ending DLC along with some new co-op DLC called Earth.
The fighting is fiercest when it’s your home at stake! Mass Effect 3™: Earth adds mods, gear, and new maps for Rio, Vancouver, and London. It features 3 new weapons: Piranha assault shotgun, Acolyte pistol, and Typhoon light machine gun. Six new human N7 classes are also available: Destroyer, Paladin, Demolisher, Slayer, Shadow, and Fury!
Sounds legit enough. Most likely though, this DLC will come at a cost. We'll be keeping an eye out for an official announcement, which shouldn't be long.
Source: Ripten.com