I made a video of my 30g tank inside and out LOL. I have a under water cam I used http://www.youtube.com/watch?v=O5Arzve8NbQ
I use the Go~Pro Hero Cam. I use it on my motorcycles when I race. If you are looking for a good cam don't get this one unless it's cheap. The Go~Pro HD is good
Ive got the Olympus pro tough cam, I use it for cliff jumping and other freshwater type activities. Yet to test it in saltwater though , it might be time to give it the ol' plunge!