Wakerboard mag had an article talking about the disposables. It was pretty good. I would start there if your on a budget.
I bought a waterproof Pentax for about 250 that takes pretty good ones, but you got to time the shutter. For anything real good I pick up my DSLR though. I do enjoy the pentax though. I put a floaty on it and it sits in my boat as the "boat camera" everyone uses it and we get great impromtu pics.