Delivering on its Un-carrier promise to change how wireless is done in America, T-Mobile has announced it will give customers the iPhone 5 for a special trade-in deal when the phone hits store on April 12. The special trade-in offer will last through June 16 and will allow well-qualified customers who bring in their iPhone 4S or iPhone 4 to get iPhone 5 for $0 down. Depending on the trade-in value of their device, customers will also receive a credit of up to $120, which can be used toward monthly payments, an existing T-Mobile bill, or the purchase of accessories or another device.