YouTube has had HTML5 video for a while. I actually like the HTML5 viewer more than their flash one. You can start using it at http://www.youtube.com/html5.
The one thing they don't have are ads for the HTML5 videos, so things like music still have to be viewed with flash.
The one thing they don't have are ads for the HTML5 videos, so things like music still have to be viewed with flash.