For video or stills?
Here's a variety of underwater housings for video cameras:
1)
http://www.dpcfilms.com/howto/ 2) Click on the "Underwater with Your Camera.."
link
- or -
For stills
1) go to ebay
2) search for "underwater hosuing"
http://search.ebay.com/underwater-housing_W0QQsokeywordredirectZ1QQfromZR8 I own the Sony SPK-PC4 (for video) and it works well. My only complaint is that I cannot fit a wide angle lens in the housing.