There are many, starting at the bottom of the price mountain with Fantasea, which includes a standard port for your kit lens at under $1000. From there, you can go on up the ladder to about $6000 for a high end aluminum housing with no ports included. Check for Ikelite, Sea & Sea, Aquatica, Subal, Nexus, etc. Then you'll need to think about lenses for underwater use, strobes compatible with each housing and lots of other fun stuff. Sometimes, you can find older housings relatively cheap on the Photo Marketplace forum here or on e-bay, craigslist, etc.