What type of insulation should I use to insulate under my kitchen floor?

I live in Portland, OR, so it gets chilly in the winter. My kitchen was added to the house in 1993, and there's a crawlspace below it. During the winter, the kitchen is cold, and the floor is uncomfortable to bare feet, so the obvious solution is insulation. Should I use ordinary Kraft R-13? How does it attach, do I just shove it up between the joists and staple it into the bottom of the floor? Or does it attach to the joists?