Fast-growing US carrier T-Mobiles latest plan to woo customers away from other mobile networks is perhaps its most headline-grabbing yet. Starting on June 23rd, T-Mobile will lend you a top-of-the-line iPhone 5S for free, for seven days. T-Mobile thinks its new scheme, called Test Drive and announced at its Uncarrier event today, will be used by more than 1 million people in its first year. The carrier says people will receive their borrowed iPhone 5S a few days later. During the week-long trial period, the iPhone will offer unlimited text, data, and calls, as long as its used inside the US.