Boy Genius Report’s Jonathan Geller has an exclusive on iPhone 5, claiming that AT&T is gearing up for an early to mid-September launch of iPhone 5. The carrier is apparently communicating launch plans to employees, Geller claims, and urging them to finish training as soon as possible:

This pretty much jibes with what we know so far, including a MacRumors story about Apple increasing retail staffing for August-September in the US and an unreliable report calling for a September iPhone 5 launch in the US (October everywhere). Apple issued the fourth iOS 5 beta over the weekend as an over-the-air update, expanded the App Store to 33 new countries, flip the switch on the Documents in the Cloud feature of iOS 5 and enabled wireless device syncing in Windows with the latest iOS 5 beta, which all signals that the company is polishing the software and smoothing out a couple of rough edges before the official release. In addition, T-Mobile USA is now cozying up to iPhone users while Verizon has been seen clearing iPhone 4 accessories stock in anticipation of iPhone 5 launch.