Many digital compact cameras have manufacturer housing that allow the camera to go underwater, check with their website.
Alternatively you may want to consider Olympus SW series that are good to 3 to 10m depending on model. These camearas also have dedicated housing that allow them to go to 40m.
Having said that, and I have one of the sw cameras, the performance is not great. I have it for convenience.
The forum general consensus view appears to be tilted towards Canon and Olympus (the non-sw models).
Digital SLR have housing made by Ikelite and other manufacturers. In many of these cases the housing cost much more than the camera.