Clive Thompson writes about the use of off-the-shelf video games for the X-box being used as combat simulation for US troops in his recent article for the New York Times Magazine:

“…The Army is already preparing plans to ship out copies of Full Spectrum Warrior to soldiers, and its creators envision the game being played by troops in Iraq, where Xboxes are popular among Americans looking to unwind. Many of the military’s young soldiers, members of the PlayStation generation, spend much of their downtime each week playing games. As the military sees it, they might as well be playing games that hone their skills. ”When a soldier is off-duty,” Cummings said, ”he’s going to go back to his barracks, and he’s going to play Tony Hawk’s Pro Skater. What if I give him a simulation instead?”
TPTB have evidently abandoned the development and use of expensive military-developed combat simulators in favour of the increasingly realistic and less costly off-the-shelf private sector games. They’ve even gone so far as to work with commercial companies to develop games, like the Institute for Creative Technologies’ Full Spectrum Warrior. The army has collaborated on a for-military-use version for use in training, where soldiers do a virtual tour of duty in war-torn Baghdad.
Says Thompson, slaughtered along with his battalion after only three minutes of play:
…the game is unforgivingly precise. The soldiers you command are programmed to respond the way a real soldier would. There are no magic weapons to bail you out. All you have going for you is the real world.
What’s next? If only we could count on virtual battles to solve the armed conflict of the future. Unreal Tournament champions as the next wave of perfect soldier. Sadly, truth being stranger than science fiction, we’d likely get the horrific scenario of Orson Scott Card’s Ender’s Game, baby soldiers trained to fight using computer simulations, only to find out afterwards that the simulations were real.
Oh, and apparently the army version is on your off-the-shelf copy of Full Spectrum Warrior, you need only do a bit of surfing to find the serial crack.