Best Buy today announced that it will become the first retail chain–aside from Apple and AT&T’s own storefronts–to begin selling iPhones in the U.S. The big box retailer will begin selling Apple’s popular handsets on September 7th, expanding the phones reach by some 986 stores (970 full-size and 16 mobile storefronts). “We had a lot of work to do, obviously, to get in a position where Apple and AT&T would feel good about Best Buy Mobile carrying it, and that’s what we’ve done in the