My guess is you'll be reading happily on your shiny new Kindle 3 on Sep 20th ...
Those of us who pre-ordered have received shipments approximately on the original dates circulated (I ordered Aug 2nd, received Aug 30; the Aug 27 shipping date changed to Sep 4 just before I ordered).
Amazon has asked the factory to make a ton of Kindle 3s so as they start to flow the timeline will drop. They not only need orders through Amazon ... they have to fill the sales funnel for Target (1700 stores), Staples (1550 stores) and Best Buy (xxx stores) so they are well positioned for November ramp-up. My guess is they have been adding a "0" or two to every manufacturing order in 2010 vs 2009.