MacRumors and other sites just posted about an early release of the iPhone 2.0 software here.
While I can’t say I recommend being an early adopter, I’ve just downloaded and installed it.
The new iPhone is about to be released (tomorrow). No, I don’t know when I can get them. I’m at least as anxious as you are, I’ve got my credit card in my hand, ready to order one as soon as they turn up for sale.
UPDATE: the AppleInsider is advising against updating at this time; with the new iPhone out today, users who update are having trouble getting the updated phones working. I suspect that’ll be resolved shortly, but hold off and check for updates here.