Though the extended preview of the Pixar animation does not come in Quicktime HD, Disney has got their own XD (Xtreme Digital) player that works well enough to show just how far CG animation has come since the early days of Toy Story.
The textures look insane and the kitchen previewed was as real as they come. The only thing that bummed me out was the player itself. For some reason the clip jumped into the recent trailer instead of closing out. I guess that's why Disney calls XD 'beta'.
I was only able to get through two minutes of the clip (nice going Disney) before it cuts off and doesn't return, but maybe you will have more luck. Hopefully Disney will stream this entire preview by the end of the week.
Check out the maybe-9-minute clip for Ratatouille over at Disney.