All together now, iPhone? Sprint Nextel will begin selling the iPhone 5 in October, sources told The Wall Street Journal Tuesday. Sprint, the nation’s third-largest cell-phone carrier, does not currently have a contract with Apple—meaning having the latest version of the iPhone could open up a huge market for the company. Verizon Wireless and AT&T, the nation’s largest cell-phone carriers, will also begin selling the iPhone 5 in mid-October, sources said. Adding Sprint as a carrier could help AT&T, once the sole carrier of the iPhone, in its bid to buy the nation’s fourth-largest provider, T-Mobile. Sprint will reportedly also begin selling the iPhone 4 at the same time.