Here's a handful of threads to go through.

http://www.coolrunning.com/forums/Forum6/HTML/024747.shtml[/URL" target="_blank">
http://www.coolrunning.com/forums/Forum6/HTML/024697.shtml[/URL" target="_blank">
http://www.coolrunning.com/forums/Forum6/HTML/024759.shtml[/URL" target="_blank">
http://www.coolrunning.com/forums/Forum6/HTML/024817.shtml[/URL" target="_blank">

3 miles in 18 minutes is a 6 minute mile pace, and you're carrying a 7:30 pace in 2 miles currently, so it's quite a ways off. You have 10 months, so try to be consistent in your running right now, getting in 3-4 days a week and maybe building to 5 for a while prior to you leaving. It's far too long and involved to get into specifics of what you need to do, but a general rule is get one good solid quick run in each week with another one good but not so hard, and the rest of your runs easy. If you can take 1 run and build up it's distance gradually so it becomes your long run, that'll help a lot with your base. Just be very wary of how you respond.

Probably a good place to start would be with a 5 km (3.1 mile) training schedule that you think you can work with. But you probably want to establish a bit of a base first for several weeks. It probably wouldn't hurt to build in some longer runs as I'm guessing that basic training will be pushing you along into some forced marches or long runs. In 10 months, you could probably go through two short, but complete periodized training "cycles" with a bit of a break in between. Just one of several approaches. I'm sure the Corps will help you out once you get there

tim