Qualified guess?
Release probably late october (last week), maybe as late as November 10th.
Regular availability; early December... They don't want to miss out on the x-mas sales, and need to push sales hard before the Nvidia 300-series-crap hits market in february
(Alright, there was some fuzz this last week about a "Fermi" on some nvidia gathering, but rumors says the card showed was mainly cardboard and plywood)