We have known for a while that Apple would be holding an event on September 10th, and that said event will more than likely be to announce the new iPhone 5S and the iPhone 5C.
Well, Apple has started sending out the official announcements for that event.
The invites obviously don't specifically say what will be in the announcement for the event, and simply carries the tag line "This should brighten everyone's day." The assumption here is that is a reference to the brighter color scheme found in iOS 7, and possibly also a nod to the various color choices that will be available for both the iPhone 5S and the iPhone 5C.
The event will be held in San Francisco on the 10th at 10AM PT (1PM EST), and obviously we will bring you all of the news of the day as it happens.