They pretty much check everything for you. Making sure you are healthy and fit for duty, during the in processing. Making sure you don't have a record, as the military is trying to clean up their look.
It was no interview process. They check your background, credit, employment and education history. You go to MEPS, once approved you are sworn in and shipped off to bootcamp.
I applied through a recruiter. The process took 2 days. I interviewed at US Navy (Nashville, TN) in Jan 2012
Interview
It's a long day and you'll have to do a few uncomfortable things. Free lunch was provided. Once you get through a long multiple choice test and longer physical screening process, someone in front of a computer will offer you one of several jobs.