According to documents obtained by Mobile Syrup, Bell and Virgin are now unlocking all versions of the iPhone for eligible customers. The policy allegedly went into effect on November 26 and requires you to pay US$75 to the carrier for the unlock. According to Mobile Syrup, customers must also own the iPhone outright, must not be on contract and must be a post-paid customer on Virgin Mobile or Bell Mobility. The unlock procedure requires you to call Bell's Credit & Prevention department or Virgin Care.
If you are a Virgin Mobile or Bell customer and can't unlock now, then you might want to wait for a few months as the leaked document suggests these eligibility guidelines will be expanded in 2013.