While there most likely won't be an official announcement anytime soon,
Gametap revealed that former EA Chicago GM Kudo Tsunoda is now with Microsoft as Project Lead for the new Gears of War game. Tsunoda was recruited by Don Mattrick, formerly at EA Vancouver, where they both worked on the Fight Night series. Mattrick also recently reeled in former Tiburon boss and EA's Vice President of Worldwide Studios John Schappert to run Microsoft's Xbox Live. According to
other rumors, GoW2 will run on Unreal Engine 3.5, have 4 new weapons, be twice as big as the original, have controllable air vehicles, new melee moves, etc...