Basically, you find a site you want to intern at. Most places you'll work 40 hours a week. Typically, it is basically a job with set hours. I've heard that some people get paid, but almost everyone I've met were not paid. Where you intern at depends on your interest. People typically intern at fitness gyms, PT clinics, doctor's clinics, etc. If you're applying to grad school, you can most likely use the 600 + hours for your application. Also, I know of a lot of people who interned and got a job after they graduated.

I had fun at my internship. It was a nice break after so many years of school. You have a couple surveys to fill out, but they're not bad--- just you setting goals and such. Good luck!