The logic behind unlocking the iPhone is its cost effectiveness. What if you plan for a world tour or go for some business trip to Europe and plan to stay there for few days. Rather than paying extra price to AT&T, you would like to take advantage of the local calls with pre-paid European card and your AT&T SIM card. Also, you may opt to use the service of cellular provider T-Mobile and not AT&T. Last year, many hackers sold the software to unlock iPhones to resellers who began to sell the software to the masses for around $100. The hackers demonstrated the method to unlock iPhones. But then another group of hackers came up, who allowed the public to unlock the iPhones free of charge with the help of open source software. In Germany, the T-Mobile cellular provider on 21st November 2007 announced that they would provide access to the unlocked phones to the public and without a T-Mobile contract. Exclusive rights were granted to T-Mobile by a German court, to sell SIM lock iPhone. In addition, they can voluntarily offer their customers to unlock the iPhone Chris Kunitz Canada Jersey , after the contract is terminated.