camera question

I am trying to buy a camera and would love some advice. I am a fairly experienced 35mm photographer, but I am starting to get interested in digital and UW photography. I have the unique opportunity coming up to sail around the world with a family as their childrens' teacher and will get to do a lot of diving as well as topside adventures.

I am looking for a camera that may be able to capture both topside and UW images for me (think African safari and Great Barrier reef). Although price is a factor I think that this opportunity warrants a fairly sizable purchase (~$1500). I am currently thinking about the Canon Digital Rebel 8.2MP and then some sort of cheaper camera for underwater, but was wondering if you had any sort of suggestions for a camera that might be able to do both.

Thanks for any advice you have. I tried to search for this information but just found way too much information.

If you want a DSLR than you are stuck buying a housing. Figure $1500 for an Ikelite plus some basic accessories, no strobes. Check scubatoys and leisurepro for less expensive point&shoot options. Check the Classified sections here, digitaldiver.net and wetpixel.com, I have bought used camera gear there for ½ of what you will pay new.

I have a prototype of the new SeaLife DC500 sitting on my desk... Amazing. 5 megapixel in a very small - "cannon elphish" sized camera with 3x optical zoom, rechargable battery, 200ft rated housing, docking station that will let you charge and download usb and video. Lots of other great features.

They are shipping in about 2 weeks, and will go out for $499...

IMHO you should take a close look at the Fuji S810 camera (6.3 megapixel) and the Ikelite housing for it, which is under $300. That price is not far apart from the Fuji housing but the Ikelite housing is a better product with never ending service from Ike.
Yes, DSLR's take better photos than point and shoot cameras BUT you can add wet mount wide angle and close-up lenses to the point and shoot thereby allowing you to make those choices underwater.
Take a look at some of the photos "Doctor Bob" takes with that camera on digitaldiver.net
He is a retired professional photographer.