The visionary lies to himself, the liar only to others - Nietzche
There are two possible dates, the optimistic one would be in pre Yule time but we are kind of running out of time on this one as there is only three weeks to go.
The second, more realistic date, would be January 2007. This would allow Nvidia to give manufacturers a chance to make a faster clocked card and the market is here to embrace it.
Nvidia still thinks it's not the time as the Geforce 8800 GTS and GTX are selling anyway but manufacturers need a point to differentiate themselves from each other. Currently everyone has reference cards with G80 clocked at the same speed and maybe a different cooler, with a different sticker on it.
We don't have any details about how far you will be able to clock the cards but we've been thinking for some time now that overclocking the G80 would be a lot of fun. ยต