According to EverythingCafe, a Best Buy employee downloaded the entire iPhone 3G S inventory broken out by store and model, popped it on his USB stick and took it home. He/she then uploaded it to Google docs for all to see. If you are planning on hitting a Best Buy, you might want to see which store has the most iPhones in the model that you want before camping out on line.
It is also interesting to see that the Black is in much greater supply (demand?) than the white. 16GB models also look to be in more demand than 32 GB as well.