I'm sure most SF lovers here are aware of
Cory Doctorow and
Charles Stross, who both have released short stories and full novels under a CC license, which can be downloaded in a variety of formats.
Then there is
Postsingular by Rudy Rucker, and many many books by
James Patrick Kelly,
Christopher Leadem,
Joshua Klein,
Richard Kadrey,
Jim Munroe,
Lindsay Brambles,
Tom Maddox,
Mike Brotherton,
Steven Brust,
Peter Watts, and
Karl Schroeder (I've tried to link these names to their respective web pages)
Perhaps not coincidentally, many of these people are also connected to the excellent
Tor Books in one way or the other.
So... any other suggestions for CCSF?