The 'Joint Battle Command-Platform', developed by MITRE, is the current device of choice. When the development kit is released in July, we expect it to become a very profitable new frontier for app development. Did you developers know that you might end up as DoD contractors?
But many are concerned about the security risks associated with using a popular smartphone operating system. They cite the risks which third party apps would pose, and the potential for even Army-purposed apps to embed malware throughout the Army's network of devices. While we normally look at rooting and jailbreaking as harmless circumventions, they could be life-threatening within the Army's network.
On a more practical note, they're still ironing out how to keep the device functional in low-signal environments. We're going to label this a work-in-progress, and assume it won't reach full implementation for quite some time.
source: Wired via Yahoo! News