IGN reports the next America's Army game will be exclusive to Xbox 360. They spoke with Randy Greenback, the Creative Director on America's Army: True Soldiers.
Randy Greenback: There were a couple key factors that led us to the decision to go out on the Xbox 360. First and foremost our experience level on the 360 is much higher, having gone through the development of GRAW and GRAW2 multiplayer. The second factor is that the installed base is much larger, which translates to a greater opportunity for a wider audience to experience the game.