AT&T is currently selling refurbished iPhones in their online store! The 8GB version is going for $249 and the 16GB version is priced at $349. With no iPhones currently in the pipeline over at Apple, this is probably the best bet to get an iPhone online. AT&T has sold iPhones at this price a few time before so I wouldn't look too much into it (read: this is in no way a rumor of Apple & AT&T cleaning out old stock before the imminent release of the 3G iPhone, though by putting this in parenthesis I'm well aware of the possibility).
Either way, $250 for the 8GB is a great deal any way that you spin it. Even if the new iPhone is forthcoming, you might be able to unlock it and pawn it off on the gray market. Or, you can keep (gasp) the soon-to-be old iPhone before everyone realizes AT&T's 3G network is not all the way there yet and that metal is greater than plastic.
As always, these puppies are available while supplies last. So what are you doing here still? Click the Read Link and buy!
UPDATE: Looks like they disappeared/sold out! Sorry if you missed the boat!