If you are interested in going to medical school it is best to talk to a college academic adviser.
If you are nearly or already accepted into medical school and are considering a career in military medicine, talk to a military physician, residency program director or chief resident. Find the military hospital nearest you and call someone. Spend time shadowing military doctors and learn as much as you can.
Each service has its own military medicine recruiting site:
Air Force Healthcare Careers site
Army Health Care recruiting site
Navy Healthcare recruiting site