no, it won't float. It'd be a good idea to put one of those foam keychain floats on it.
I've got the 5mp wide and an HD, but haven't had much chance to use the HD yet. The wide is super versatile, but I wouldn't say it's a replacement for a true video cam. The reason being that there's no zoom and it's a fisheye lens, so it's really best for capturing what's happening right in front of the camera (say 10' ish). If you are 30' away, it looks like you are a mile.