This is One Force Tracker, a cool military iPhone application that shows friends and foes over maps in real time, and provides with secure communications. This is how it works, according to Raytheon Intelligence and Information Systems's CTO J Smart:

This is hypothetical, but if there is a building with known terrorist activities, it could automatically be pushed to the phone when the soldiers get near that area. If there was another platoon that was supposed to arrive, and they were delayed, or ahead of schedule, you could adapt your plan. If one of the units you are counting on is redirected, you know that in real time.

He points out that it can also be used for police, firemen, and emergency services too. The iPhone itself is being retrofitted for battlefield operation by Raytheon, which is adding a ruggedized case that includes a larger battery and a special scrambler that will secure communications with other military units. [NYT]