Details of the EOS 5D Mark III's specifications were leaked prior to its official release today, and they ended up being pretty much on the mark; it's a 22MP serious DSLR with an equally serious price point. I got some brief hands-on time with an early sample of the EOS 5D Mark III late last week, and it's an impressive camera for the serious photography set. The Mark III uses Canon's DIGIC 5+ Image Processor with an ISO range of 100-25600. It's also Full HD Movie compatible. Canon's extended the autofocus up to a 61-points, and it's capable of 6fps continuous shooting.
The 5D Mark III is dust resistant, but not IP rated for that specific resistance, will take both CF and SD cards, and has inbuilt HDR functionality, as well as multiple exposure modes that allow for some interesting creative photography possibilities. Of note, the 5D Mark III's not a strict replacement for the 5D Mark II; Canon representatives told me that both will still continue to be on sale beside each other.
As for pricing, the 5D Mark III will cost $4399 for a body only kit, $5499 with a 24-105mm lens or $6899 in a 24-70mm pro kit configuration. It's expected to be available in late March -- most likely the 22nd -- except for the pro kit, which will go on sale in April.
Also on sale in April, Canon's announced a new Speedlite to go along with the 5D Mark III; the $849 600EX-RT, which replaces the 580EX II model. It's an RF-based flash unit capable of working up to 30m away from the camera. It can be paired with the new $379 ST-E3-RT, a Speedlite wireless transmitter as well. [Canon]