As of September 2, 2011, the paperback edition of Photographer’s Guide to the Nikon Coolpix P500 is listed as available for shipment within 24 hours at the bn.com (Barnes and Noble) web site. I ordered a copy to see if that listing is real, and not just an announcement of future availability. I soon got back a confirmation e-mail saying the book is scheduled to ship on September 7, which leads me to believe the book really is available now through the pipeline from the printing company to online retailers.
So far, I have not seen the book show up at Amazon.com, but I will post further information as soon as I have it.