I have used
http://www.bhphotovideo.com/c/catego...otography.html
for two sets of camera and enclosures for the past 5 years. I found the best trade off in usable mid end camera that fits a $150 housing. Great for snorkeling and shallow dives, not reliable at 60 to 100ft I have been told. Currently using an A710IS with housing. It takes great pictures in the underwater mode and cost $400 total. It is also a great general purpose camera for someone who normal lives by his Cannon digital SLR with excellent lenses.
This combo is much better than the disposables and after spending $100 in our first year, this is much better, more photos to chose from, better quality, and better results than the disposables.