Damien
This is quite entertaining but it's worth noting at 10 metres (30 feet) the water pressure exerts a pressure of 30 pounds per square inch (note sea level pressure is about 15 pounds). A leak is going to flood the bag very quickly...
I have purchased disposable waterproof film cameras for snorkeling which are okay as long as you don't go to far down on one breath - but as a qualified underwater photographer I'm also going to note that underwater housings for DVD cameras and SLRs start at USD 2000+ esp ones rated to say 150 fsw which is about what I'm allowed to do under recreational dive rules.
Also wide angle lenses suited to underwater photography with a low enough F-Stop are usually very exxy and also require underwater strobes (or in our case HID lamps)... have a look at myspace page:
www.myspace.com/replicant_008 for a shot taken at around 30 metres on the wreck of the Rainbow Warrior for a idea of the kind of shots that we've taken in the past...