Found this via TeleRead
From Arthur C. Clarke to Ursula Le Guin and Jerry Pournelle, well-known sci-fi authors have made freebies available on the Web. Find many of these works via Free Speculative Fiction Online.
From the Free Speculative Fiction Online site:
All stories are available for free. This site does not link to pirated SF! Sites violating the copyright of the respective stories by making them accessible without the author's and/or publisher's agreement are not included.
And there's even an RSS feed for new additions!
(oh and check out the crazy chart I found for all you uber nerds out there -- size comparison chart of movie and tv space vehicles)