I’m running across a few military amateur radio clubs:
K4AF – The Pentagon – http://www.k4af.org/
K2KGY – West Point- http://www.eecs.usma.edu/webs/clubs/hams/
W2USA – Fort Lewis, WA – http://207.108.217.210/w2usa/index.htm
It also looks like there are other stations out there:
K2USA – Fort Monmouth, NJ
K1KBO – Fort Huachuca, AZ
K5USA – Fort Sill, OK
K4WAR – Fort Gordon, GA
K5WAC – Fort Bliss, TX
W5USA – Fort Sam Houston, TX