When you sell your cellular phone, especially a smartphone, it's best to either wipe the system of all personal data before hand or sell it with a seperate SD card. Then when you get a new phone, replace that SD card with the one you had before to backup your own data.
Sadly this isn't possible as Apple want to make a profit from the music they sell.
Kill monsters and sell the items they drop
AT&T doesn't sell the iPhone 3GS in white.
No
Probably so that they'll sell more than other shops that sell it and make more money :)
sell your Iphone and get an Android phone
No, but you can sell your iPod for iPhone money.
Because of the new technology of new iphones,and free iphone 4s I believe that they do not sell the iPhone 2G.If its a low product standard then it wouldn't be the iPhone 2G,it would be the iPhone 3G.
sell it you get money out of it!
at a store
I don't believe any carriers still sell the iPhone 3GS or older, especially considering they offer the iPhone 4 now for free (with contract).
You can sell your old iPhone on amazon.com. Find your model and then list it in the used section. You can also sell it directly to ebay.com or list an auction.