While we're on the subject of LucasFilm, EMusician Xtra links to Filmsound.org's Star Wars special.
Highlights: The screech of a TIE fighter is a 'drastically altered' elephant roar, and a brilliant bit about Ewok language, which is an electronic composite of Tibetan, Mongolian, and Nepali. Elsewhere on the same site is this interview with sound designer Ben Burtt, where he goes into more detail about Darth Vader and Lightsabres...