The official Youtube account now has scenes from each movie in HD. I’m not embedding them because you have to go directly to Youtube to select the HD version (Example in the screenshout above.) Check them out: The Phantom Menace, Attack of the Clones, Revenge of the Sith, A New Hope, The Empire Strikes Back and Return of the Jedi.
There’s a new extra posted as well: A feature on the Acklay creature from Attack of the Clones. That’s available in HD as well, but there’s an embed under the cut.