AT&T has refurbished 3G iPhones up for sale
on their site. The 8GB black sells for only $149 with a new 2 year contract, and both the white and black 16GB versions are $249 with contract.
A "refurb" is defined by AT&T as:
They've got free overnight shipping with 2 year contracts as well - so get it in plenty of time for Christmas.