I'm an USAFA 2010 appointee in the same situation. I'll give you some info from what I have learned. First, if you graduate with a high class rank, that is crucial to going into Med School directly AND you need to have a good MCAT score for the Army to consider sending you . The two choice available are military paid civilian med school (ie harvard or Johns Hopkins) or the Uniformed Services University (USU). Civilian route incurs another 4 years of service on top of the 5 years from the academy (you do not start repaying this until AFTER med school) and the USU incurs another 7 years.
Here's a good link. This is for the Air Force, but I'm sure it is similar for the Army. http://www.usafa.af.mil/df/dfb/medical/afcareer.cfm