I want to take a dslr camera in a housing underwater with me when I scuba dive. I hear that some cameras are better for underwater use. If this is true I'd like to know which camera will be the best.

An excellent DSLR camera is the Olympus E520! You can find it at Buy .com selling for $479.00 and FREE SHIPPING!
specifics are:
EVOLT E-520 Digital SLR Camera Zuiko Digital ED 40-150mm F4.0-5.6 Lens Zuiko Digital ED 14-42mm F3.5-5.6 Lens Li-ion Battery BLM-1 Li-ion Battery Charger BCM-2 USB 2.0 Cable Video Cable Shoulder Strap CD-ROM Instruction Manual Registration Card Lens and Body Caps Lens Hood Eyepiece Cap EP-4

The E-520?s industry-leading Image Stabilization technology, which is built into the camera body, compensates for movement so you can capture blur-free shots with any lens even at slow shutter speeds. Autofocus Live View brings subjects into sharp focus; it is the perfect tool for macro, portrait or even landscape shooting. This camera was built to produce amazing results for photo hobbyists and serious digital photographers alike.
Features
Image Formats   JPEG RAW Screen Size   2.70" Package Contents	Image Formats   JPEG RAW Screen Size   2.70" Package Contents	Manufacturer		Olympus Corporation
	Memory Card Support		Microdrive xD-Picture Card CompactFlash (CF) Card
	Interfaces/Ports		1 x Proprietary
	Maximum Image Resolution		3648 x 2736
	Display Screen Type		Active Matrix TFT Color LCD
	Number of Batteries Support		1
	Viewfinder Type		SLR
	Flash Modes		Auto Flash Flash ON Flash OFF Red-eye Reduction
	Manufacturer Part Number		262090
	Standard Warranty		1 Year
	Dimensions		3.60" Height x 5.40" Width x 2.70" Depth
	Manufacturer Website Address		http://www.olympusamerica.com
	Battery Size Support		Proprietary
	Product Line		EVOLT
	Display Resolution		230000 Pixel
	Weight		1.05 lb
	Effective Camera Resolution		10 Megapixel
	Optical Zoom		3x (Lens 1) - 3.8x (Lens 2)
	Battery Include		Yes
	Product Series		E
	Battery Rechargeable		Yes
	Product Model		E-520
	Total Camera Resolution		11.8 Megapixel
	Product Name		EVOLT E-520 Digital SLR Camera
	Image Stabilization		Optical
	Auto Focus Points		11
	Focus Modes		Auto-focus Manual Focus
	Product Type		Digital SLR Camera

 
Tech SpecsEVOLT E-520 Digital SLR Camera Zuiko Digital ED 40-150mm F4.0-5.6 Lens Zuiko Digital ED 14-42mm F3.5-5.6 Lens Li-ion Battery BLM-1 Li-ion Battery Charger BCM-2 USB 2.0 Cable Video Cable Shoulder Strap CD-ROM Instruction Manual Registration Card Lens and Body Caps Lens Hood Eyepiece Cap EP-4Portrait Landscape Landscape + Portrait Night Scene Night + Portrait Children Sport High Key Low Key Digital Image Stabilization Macro Nature Macro Candle Sunset Fireworks Documents Panorama Beach & Snow Underwater Wide Underwater MacroAuto ISO 100 - 1600 Manual ISO 100 - 1600, 1 EV steps Menu Languages (Americas): English French Spanish Portuguese Multi-Connector: USB Video Out

Package Contents	Package Contents	Screen Size		2.70"
	Software Included		Olympus Master 2
	Camera Modes		Scene Modes:	Interfaces/Ports		1 x Proprietary
	Focal Length		14 mm to 42 mm (Lens 1) - 40 mm to 150 mm (Lens 2)
	Image Formats		JPEG RAW
	Manufacturer		Olympus Corporation
	Memory Card Support		Microdrive xD-Picture Card CompactFlash (CF) Card
	Lens Construction		10 Elements in 8 Groups (Lens 1)12 Elements in 9 Groups (Lens 2)
	Number of Batteries Support		1
	Shutter Speed		60 to 1/4000 Second
	Standard Warranty		1 Year
	Flash Modes		Red-eye Reduction
	Viewfinder Type		SLR
	Flash Modes		Auto Flash Flash ON Flash OFF
	Manufacturer Part Number		262090
	Additional Information		Sensitivity:	Display Screen Type		Active Matrix TFT Color LCD
	Maximum Image Resolution		3648 x 2736
	Aperture Range		f/3.5 to 5.6 (Lens 1) - f/4 to 5.6 (Lens 2)
	Battery Size Support		Proprietary
	Manufacturer Website Address		http://www.olympusamerica.com
	Dimensions		3.60" Height x 5.40" Width x 2.70" Depth
	Display Resolution		230000 Pixel
	Brand Name		Olympus
	Optical Zoom		3x (Lens 1) - 3.8x (Lens 2)
	Weight		1.05 lb
	Battery Include		Yes
	Product Line		EVOLT
	Product Series		E
	Battery Rechargeable		Yes
	Image Stabilization		Optical
	Product Model		E-520
	Effective Camera Resolution		10 Megapixel
	Platform Support		PC
	Product Name		EVOLT E-520 Digital SLR Camera
	Total Camera Resolution		11.8 Megapixel
	Auto Focus Points		11
	Focus Modes		Auto-focus Manual Focus
	Product Type		Digital SLR Camera

This model has a great underwater housing that would be PERFECT for scuba! You can find it for $619.99
specifics are:
The Olympus PT-E05 underwater case has been specially customized for the Olympus E-520 and is waterproof up to a water pressure equivalent to a depth of 40 meters. With its durable, high quality polycarbonate construction, it protects the camera from water while also cushioning it from knocks and bumps on land.

As a genuine advantage to the underwater photographer, the photographer can make use of the Live View function and use the large 2.7"/6.9cm LCD instead of the viewfinder. The flash connectors allow optional use of up to two UFL-2 underwater flash units. Five interchangeable lens ports allow the optional use of 14-42mm, 14-45mm, 11-22mm or 14-54mm, 7-14mm, 8mm Fisheye and the 35mm as well as the 50mm Macro lens.

	E-520 Underwater case body
	Waterproof up to 40m
	Semi-transparency poly-carbonate
	Front cover and back cover, locked by a rotary buckle
	Two optical fiber connectors