For a while now there has been buzz over the net about an iPhone software unlock solution but nothing was available until now. The people over at iPhonesimfree.com have successfully unlocked the iPhone using a software program. Before this the only way to unlock your iPhone consisted of opening up the phone and soldering to the motherboard.
iPhonesimfree.com is offering unlock codes to resellers but the minimum quantity is starts at 50 with price breaks at 100, 250, 500, 1000, 2500, 5000.
If you wish to purchase just one the price is around $100 depending on where you get it from. There is no way of knowing that the phone will stay unlocked after updating your OS through iTunes in the future but only time will tell.