We've already seen the Pentagon approve one single customized Android device for use, and now CNN is reporting that US troops may be getting Android devices as soon as this year. It seems that the government has been testing out smartphones for a while and Android fits the needs best because it can be so easily customized. Apple reportedly wouldn't allow the government access to the iOS source code, so the necessary tweaks and customizations weren't possible on Apple devices. However, Android's open structure means that the government can dig in and do whatever it needs to suit its purposes.
The plan is that the government will use commercially available handsets that are loaded up with the heavily customized and locked-down Android builds that the government puts together. It seems that one of the only sticking points right now are in securing voice calls as most other uses have been secured to the government's liking.