Confirmed: AT&T offers complimentary unlock of in-contract iPhones for deployed military personnelBy Z. Lutz, 09.10.2012
AT&T to begin unlocking off-contract iPhones this Sunday, April 8th (update)By A. Munchbach, 04.06.2012
Sprint explains iPhone 4S unlocking policy: phones will be unlocked, then locked, then unlocked againBy Z. Honig, 10.13.2011
Sprint and Verizon confirm iPhone 4S Micro SIM unlock for international travel (update: Sprint remains locked?)By Z. Honig, 10.12.2011