Free as in Freedom - the online version; it's covered today on Salon. Was hard to track down the actual online copy - none of my searches on Google turned up the oreilly page; I probably should have thought to go directly to the publisher for the open version (which Stallman apparently insisted upon).
You can download this book from Gutemberg Proyect at
http://digital.library.upenn.edu/webbin/gutbook/lookup?num=5768
cheers