The trailer for the Robot Chicken: Star Wars special is out:

Robot Chicken: Star Wars trailer

Robot Chicken: Star Wars trailer (much better quality)

"Robot Chicken" Star Wars-Themed Special

People doing voice work for the special include:
George Lucas (as himself), Conan O'Brien, Seth MacFarlane, Malcolm McDowell, Hulk Hogan, James Van Der Beek, Robert Smigel, Donald Faison, Abraham Benrubi, Breckin Meyer and Joey Fatone.

They did the special with the full blessings of George and his Empire, allowing them access to all sorts of Star Wars goodies for the special.