Conceptual drawings for Star Wars
Here is a nice video with the conceptual drawings of Ralph McQuarrie. “Ralph McQuarrie (born June 13, 1929) is a conceptual designer and illustrator who designed Star Wars (all of the original trilogy), the original Battlestar Galactica (TV), E.T. the Extra-Terrestrial and Cocoon, for which he won an Academy Award.” (from wikipedia)
Home page of the artist: http://www.ralphmcquarrie.com.
I found this video in this post (in Hungarian).