Developer Chronic is offering AT&T iPhone 5 unlocks.
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While being the source of a lot of iOS news (and entertainment), Chronic is also a hardworking developer/hacker helping iOS users get out of jams. His latest foray is into iPhone carrier unlocking. GSM carriers such as AT&T in the U.S. or Fido and Rogers in Canada or others such as Koodoo or Telus can be unlocked including the just released iPhone 5. Since each carrier requires a different process, the fees vary widely.
You can email [email protected] for prices and availability for their GSM carriers.