AT&T is planning to launch a new iPhone during the third or fourth week of September, claims a source with the US carrier. The person remarks that the company is maintaining an all-hands-on-deck schedule for its workers during that time period, one that will extend all the way into mid-October. A second source adds that a large training event for regional workers has in fact been rescheduled from the first week of October as a result of a conflict with a "huge announcement."