Woody2000, top find. I saw that video last year then it got pulled for copyright infringement, glad it's up there again. He's actually not going that fast (the time clock and distance covered gives you an idea, it's just under 40mph for a lot of it) but he's SO smooth, perfect control and you just know that if a mere mortal tried staying on his wheel they'd be over the edge in no time!
Watch the full coverage of the mountain stages, quite often the moto cameraman will point the camera down at the bike speedo, you can see it at 50mph/80kph regularly on the descents. Average speed for most stages is about 40kph/25mph although the first hour of a stage a few days ago was run at about 50kph average as they tried to get a break established. That was properly quick, you could see how hard they were trying.