According to this site, back in the Return of the Jedi days...
George Lucas sued by Dean Preston: George Lucas had to appear in a Canadian court to defend himself in a $129 million dollar copyright infringement case in which Canadian writer- producer, Dean Preston, alleged that the Ewoks, the cute, furry, and rather irritating teddy bear-like creatures featured in Lucas' Return of the Jedi, were his own invention. Preston alleged the Ewoks made their debut in his screenplay, Space Pets, which he said he had mailed to Lucas five years before the movie's release.
The summary court brief can be found at http://www.robic.com/publications/Pdf/142.005.pdf and here's a break down of the 'facts' which went into deciding the similarities between ideas: http://www.geocities.com/melanie_lawnotes2/CopyrightNotes.doc
Space Pets vs. Star Wars
Chi Chi Gomez! Love it.
Needless to say, Lucas came out on top of all this.
* Today's Flashback is courtesy of my friend Peter A. Lopez who did most of the research you see here.