Virgin Mobile Canada and Bell Canada will unlock your Apple iPhone once you unlock your wallet
that is still active. You also must be a post-paid Virgin Mobile Canada or Bell Mobile customer. Then, and only then, are you allowed to make a $75 credit card payment.
The process is as simple as icing the puck. After you make your payment, you give the carrier your phone's unique IMEI number and then restore it in iTunes. Other Canadian carriers have already offered to unlock the Apple iPhone with Rogers and Fido starting all the way back in December 2010 for $50. each Telus added the practice this June for $50, a charge that has since been reduced to $35.
In the U.S., filling out a simple online form from AT&T lets you request the free unlocking of your AT&T branded Apple iPhone.
source: iPhoneinCanada via MobileSyrup