iPhone 4 orders reduced by 10% in anticipation of the next iPhone, which might launch September 7th
If tradition is followed by Apple, the usual iPod refresh event it schedules in the fall, could be replaced with an iOS 5/iPhone 5 launch fanfare. The iPod-related stuff will then play second fiddle, or, seeing how there was no mention of a new iPod model in the iOS 5 code, might be sidestepped altogether. These events are usually taking place on the first Tuesday or Wednesday after Labor Day, with Wednesday taking precedence, so we might indeed see a joint iPhone 5/iOS 5 launch on September 7, to give Apple a headstart before Google's next Nexus phone.
source: RedmondPie & CNETUK