I picked up my Ikelite housing for my Nikon D40 yesterday. Today I took it into the pool to mess around with it. Two things became clear to me while messing around in the pool: (1) underwater photography is going to be a lot of fun and (2) underwater photography is going to be a bitch to learn. I had another realization yesterday in the camera shop: underwater photography is going to cost me a lot of money.
The clear housing was good for peace of mind as I could see that the camera was dry the entire time. When the camera is enclosed in the housing, it's difficult to see what button is what, so familiarity with the camera is going to be key. I would also imagine not wanting to mess with the settings too much while underwater.
Here's a self portrait I took today:
I am quite looking forward to trying the camera out on my next dive trip, which will be on the Black Manta, October 19-21, where we will be going to the Seven Skies and Igara.