As T-Mobile prepares to officially offer the iPhone for the first time, it's trying to pump up the lure with a trade-in offer for owners of the 4 and 4S models. Available through mid-June, the promotion lets iPhone 4 and 4S owners trade in their current device for an AWS HSPA+ friendly iPhone 5 for no money upfront (with monthly payments) under its new no-contract Simple Choice Plans. Additionally, depending on the condition of the hardware being traded in, customers can get a credit of up to $120 to be used against those payments (knocking it down to $15 from $20, for example)
