All signs point to an iPhone 5 announcement in September

 
All sources point to yes, they iPhone 5 will be unveiled during the pre-scheduled Apple press-event being held this coming September. 
 
Apple will hold a press-event for the new iPhone on September 12, 2012. Numerous websites including The New York Times, have reported ‘unnamed’ sources close to the company that state the new iPhone will be launched on this date.
 
Apple has repeatedly launched iPhone products during the fall, the last iPhone 4s was launched on October 4, 2012.
 
source | NYT