Yep, what Pat said. The replacement "mops" are available for about 4 bucks if you call them directly. I have also seen them on a couple other online retail sites but don't remember which ones.
I just got one, and while it works ok, I feel more comfortable with my sheepskin mitt. The other problem is, how do you dry? I still used a stool to do it.
This is the problem I had as well, almost... I still needed a horse platform to use the versa mop (I'm 5'7" and the minivan is not that mini ;-) ). After washing with the mop, I too was confused how to dry the thing. Ended up tossing a MF WW across the roof and dragging it (took alot longer than using the mop). The mop was good.. It allowed me to wash the roof and the upper middle part of the windshield.