I miscarried last March (I ended up getting pregnant 2 weeks later). I didn't have the D & C (I was scheduled for it, but I passed everything the day before the appointment). My Dr. was really adament about the D & C, saying that my bleeding would stop, and that there would be little to no pain. From my experience, the cramping got pretty bad (they felt like labor contractions, which they were to some degree), I passed a lot of clots and I saw the baby after he/she was expelled. I really didn't want the D & C, mainly because it would have been my first surgery, but looking back, I think I would have chosen that option (assuming that my body wouldn't have expelled everything on its own). I know I wasn't much help, but I wanted to tell you my experience since the other posters have had the D & C performed.
I'm really sorry that you are going through this. If you want to talk, please feel free to PM me!
Christina
EDIT: I forgot to mention that I bled for a week or so, where as with the D & C, the bleeding is supposed to stop.