I am trialing a new waterproof case for iPhone4 and 4S called Elite Pro111. The conditions were ok and I was lucky enough to see some interesting fish and a sea dragon at about 5 meters deep. The video and picture quality of this waterproof iPhone case is excellent and the case is rated to 10 meters which is deeper than most.
Australia:
http://www.waterproofiphonecase.com.au
USA/International: http://www.waterproofcaseforiphone.com