Post here if you're buying an iPhone 3G S on eBay.
There are many for sale by people who have pre-ordered and are picking them up on the 19th, then shipping them to eBay buyers overnight so they get them on the 20th.
cheapest buy-it-now i found was $750 for the 32gb. not bad... the unsubsidized price of the the 32gb ($699 + sales tax in some states) would mean that ebay is a better option.
I got mine for $725 on eBay, but the guy who was selling it sold out of all of his. I've been talking to him and he is using his family upgrades to get it so he is paying $499 and making $725, so he's clearing $226, not bad deal for either of us....