The sources say that Apple has been considering either October 7 or October 14, but with the supply side moving forward smoothly, Apple may consider shooting for the earlier date. Pre-orders for the next-gen iPhone should kick off in the final days of September, but Apple is still considering between either Thursday September 29 or Friday September 30—the latter is looking more likely.
The iPhone 5 launch time frame has been going back and forth between September and October with plenty of dates having been thrown around, including September 7 as well as September 12. However, the well-connected AllThingsD has adamantly insisted that the iPhone 5 would not ship until October.