The Last Colony is the final novel in the sequence begun with Scalzi's Hugo-nominated debut Old Man's War and continued in the sequel The Ghost Brigades. It will be published in hardcover by Tor in May 2007.
There will be normal advance review copies several months from now, but at the moment this is the one and only copy being made available to anyone other than Scalzi's family and his publisher.
As bidding hits $500, $1000, or other ratchet points, Scalzi has promised to add other rare Scalzi-related objects to the lot. Details in Scalzi's post, the comment section of which is where the actual auction is taking place. The auction began late last night and, as of Tuesday morning, is up to $280. It will run through next Monday.