It should be a great camera to take pictures uw with. The prices of DSLR housings is very high. Normally it is same price as the camera, sometimes it is more expensive.
For DSLR's, the price of the housing is about three (Ikelite) to six (Nauticam, Subal, etc..) times the price of the camera body. This is why the camera body is considered an accessory for the housing...
The 30D was a great camera in 2006, and is still a fine camera for topside photography. My first underwater DSLR was a 10D in an Ikelite housing, and it was terrific. That having been said, if you are going to get into DSLR underwater photography today, you are going to have to spend a minimum of $1400 for a new Ikelite housing alone (not counting the dome port). So the question you need to ask yourself is how committed are you to this project, and do you really want to house the DSLR just because you have it. Remember, you may also need new lenses, depending on what you have now. You will be spending a lot of money to lock yourself into a five year old DSLR, and a lot of improvement has happened in those cameras over the past five years...
For far less than the price of a 30 D housing alone (not even considering a dome port for wide angle, a flat port for macro and strobes), you can get a complete underwater compact camera ("point and shoot") in a housing with a flash. Yes, it won't do what a DSLR will do, but if you are just starting out it will probably be a long time before you are limited by the camera.
I would recomend ikelite housings or sea&sea housings. You don't want to compromise the quality and risk a flotted camera. Go to Ikelite.com there you can find more info about the product.
Best of luck with it all..
Ikelite housings are very good equipment, but they are half the price of most of the metal housings. Most floods are operator error (mine was!) or occasionally o-ring maintenance issues, not due to the housing brand...
Good luck!
Mike
