what in the world do they feel like?!? I'm 34wks today and I think I've had one... and that was yesterday. It was actually painful, but everyone describes them as 'painless cramps', as care_free so eloquently put.
Newbaby, as long as your water doesn't break, call the hospital first. I know my hospital likes you to labor at home for as long as possible before actually going in.

good luck!