I don't think anyone here can give you a sim unlock code. Unless you want to pay for it you can buy from ebay.
Here's the free solution. http://pof.eslack.org/hermes-unlocker/
Run this unlocker on your phone. Follow the instructions exactly. Don't unlock the CID unless you planning on installing another custom rom other than ATT on it.
Answers & Comments
I don't think anyone here can give you a sim unlock code. Unless you want to pay for it you can buy from ebay.
Here's the free solution.
http://pof.eslack.org/hermes-unlocker/
Run this unlocker on your phone. Follow the instructions exactly. Don't unlock the CID unless you planning on installing another custom rom other than ATT on it.