A Massively Multiplayer Online Game (MMOG) for the military has been proposed by Army game-designer Dr. Roger Smith.
"Potentially an MMOG could be created which adheres to the physical and behavioral reality of the world and provides an 'always on' environment in which to execute training, something like World of Warcraft, but focused on the military training customer," says Dr. Roger Smith.
The idea being put forward here is that the military can have a huge server farm (or set of them around the world) that would let any American soldier log on, and be immersed in any of a variety of training scenarios in a virtual reality world similar to that of Second Life and other such programs. The exercises could be entirely theater-specific; see the video below, which shows a Tactical Language Training session.
(Tactical Language Training system capabilities)
Trainees can rerun the same scenario over and over to see what happens by making different choices; the package that is shown above purports to teach over 2,000 Arabic words.
It is even possible that soldiers using the system could interact directly with human experts who are also logged into the system, by using digital avatars.
I can think of several science-fictional precursors to this idea. In The Dosadi Experiment, Frank Herbert's protagonists make use of a military and personality simulation program. I think that this kind of quick access to experts and information is also seen in A Matter for Men, a David Gerrold novel about alien invasion. William Gibson presents a realistic virtual meeting in a jungle in Idoru. I also kind of liked this virtual reality tea ceremony from Rim by Alexander Besher; it would be a great way to learn the customs of a foreign people.
It would be sort of weirdly cool if the US military could get together with terrorist groups to agree on standards and protocols; that way, troops and police officers could actually take on terrorists on their own virtual world turf. See this article on Codename 'Reynard' - Hunt Terrorists In Virtual Worlds regarding efforts to watch terrorists attempt to use virtual reality for their own ends.