You MUST check this out: Star Wars Origins. The amount of work and research put into this site is simply amazing. There’s nothing really groundbreaking, but it’s a far more complete look at the origins of the saga than any other article or site I’ve ever seen – including the Magic of Myth book.
In depth looks at many of the things that influenced (or may have influenced) Lucas: Campbell, Flash Gordon, Kurosawa, 2001, Ben Hur, Lord of the Rings… And more. Brilliant, wonderful site. Why have I never heard of it before???