ARLINGTON, Va. — One of the most dangerous jobs in Iraq is acting as a gunner during convoy movements. Even up-armored Humvees, which provide added protection for most of the crew, leave the gunner exposed. But for the gunners assigned to four special up-armored Humvees in Iraq, convoy movements are a different experience: instead of spending the drive hunched in the turret, scanning their sectors and hoping for the best, these soldiers are comfortably seated the back of the vehicle, eyes glued to a computer screen and right hand on a PlayStation-like joystick. If the gunner, or someone else in...