I got mine unlocked from AT&T. Just tell them you took it off eBay or something, calling from outside US and never plan to use their service as you won't be travelling to US. They took my request without any hiccups. It took 15 days for the request to process but totally worth it.
Thanks Rohit. I will try the same, but how can i know version and firmware of my phone. sorry but i dont have any knowledge about phones so I am asking it to u. and what information they will ask from me?