|The complete works of Charles Darwin have been posted by University of Cambridge for your free perusal. The cool thing about this is that it isn’t just in plain old text format. You can also choose to view the text along side a scan of one of the original published books. They’ve got the text to multiple editions of The Origin of Species ,The Descent of Man, and even his field notebooks from the Beagle voyage.
Good stuff here. They also state that only about 50% of the material has been published, and are promising to get everything on the site by 2009.