My experience is that when I uploaded a HD video, it was immediately available in 360p... I did some searching and Googling to see how to enable viewing at a higher resolution. I finally discovered that "in the background", Stream is working on making the HD versions of the video available (and indeed the HD version was available ~20 minutes)... I would like to suggest that Stream indicate to the users "HD processing in progress" or something like that, just to let the user know that 360p isn't the only resolution that will be available.