We now factory unlock any AT&T; iPhones as 2G, 3G, 3GS, 4 and iPhone 4S for only $155.00 
The factory unlock services works exactly the same way as you buy a factory unlocked iPhone from Apple store .
Once it is factory unlocked, you could update and upgrade it anytime thru iTunes without losing the unlock, because it would be permanently unlocked.

If interested,, please contact us at 
ES-Wireless 
333 Broadway Revere, MA 02151

Ph: 781-629-2950
www.es-wireless.com