Here is the latest info I have on X-Box 360 game release dates.

    Game Release Dates
X-Box 360 Elite               April 29
Shadowrun                     May 29
The Darkness                  June 1
Rogue Warrior                June 1
Mass Effect                   June 19
Overlord                         June 26
BioShock                       Aug. 21
Blacksite: Area 51          Sept. 3
Frontlines: Fuel of War    Sept. 3
Dark Sector                    Sept. 4
Turok                             Sept. 18
HalfLife 360 Bundle          Sept. 24
Jericho (Clive Barker)       Fall
Timeshift                         Oct. 2
Grand Theft Auto IV         Oct. 16
Halo III                            Nov. 1
Mercenaries II                  Nov. 1
Army of Two                    Nov. 1
Splinter Cell: Conviction      2007
Unreal III                            2007
Haze                                  2007
Huxley                               2007
Crossfire                            2007   
Cipher Complex                 Holiday '07
Sacred II: Fallen Angel      Q1 '08
Spore                               07/08?
Fable II                             2008
Duke Nukem                     Holiday '08
World of Warcraft               Holiday '08
Project Offset                     2008?
Fallout                               2010?