There's info on it at
www.goarmy.com
I got into it by being prior service navy. pre-req is that you are prior service, have completed boot at last or current branch of service, and if you are still serving for your last branch. It's pretty easy, just talk to a recruiter and they can get you more info on it.
Oh, a couple more good websites to find out more info is
www.military.com and
www.usmilitary.about.com
Hope this helps.
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By the way, It doen't matter what your rank was in the Navy or any other branch. If your rate crosses over then you stay in it, usually. Otherwise, they will retrain you into a new MOS.
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