Medscape.com, not to be outdone by WebMD's promotion of free full text access to Scientific American Medicine (limited time – see link below), is now offering Medscape members (free registration) access to Harrison's Online (HOL) through May 8th. It's tough to find on the medscape website .. once you have logged in the to medscape, access Harrison's for free by using this link: http://www.medscape.com/HOL/public/HOL-about.html.
I find the interface to Harrison's to be preferable to SAM, but they both suffer from the "I used to be a textbook" problem: lots of clicking "next" to view to see the next page. With Stat-ref's superior user interface, there is not nearly so much clickety-clicking as one sees in HOL,SAM, or even MDconsult.