It really depends on what you'll use it for. If all you want is a couple shots of Mickey in the CC snorkeling lagoon, then save your cash and just get a disposable - it'll be adequate.
If you like snorkeling, beach days, waterparks, etc., then I'm going to throw my weight onto the Kodak play/sport. My dad bought one for me last year, and I was impressed with how good it was for the price point. Photography is a hobby of mine, but DH isn't too great with it, lol...but both of us managed to get some great shots. It's easy to use, even one-handed! Also, the greatest thing about it to me was that it takes video and then allows you to pull out still photos from that video and save them as a separate file, right on the camera. I have some BEAUTIFUL shots of the characters that I pulled out of videos of them dancing at the NYE party, for example. It works great for snorkeling, swimming, and general use - but it's only waterproof up to 3m deep.
If you're into deep water activities, like scuba diving and such, then you'd be doing yourself a great favor by going with a camera designed specifically for underwater usage - like a Sea Life camera or similar. It doesn't sound like that's your intent, though. So you really don't need to toss a bunch of money in that direction.