How do I evict a roommate?

Question Details:

I got a roommate in in mid-October; no signed agreement and no rent paid (they wouldn't pay without agreement). I now want the roommate out. She has practically no belongings. I invited her to stay with the understanding that we would eventually sign an agreement. Since that time, no signed agreement and no rent money at all. What is her status (roomer/boarder vs renter/ tenant)? Do I serve her notice, and without a lease, how much time to vacate (now, 7 days, 10 days, 30 days)? Can I just change the locks and set her stuff on the porch? Important Notice