The announcement is juust around the corner but it looks like Apple itself has leaked a bit of info regarding the next iPhone: it looks like iPhone 4S images have appeared on Apple's website and that Apple's Japanese website has leaked the iPhone 4S October 14th launch date too.
9to5Mac was first to notice the new iPhone 4S images on Apple's website—the pair of images show a black and white iPhone 4S, which look exactly like the Verizon iPhone 4 with its antenna placement, can be seen here:
The old iPhone 4 images are the same exact URL but without the 's' after 'iphone4s'. Those images are here:
The only differences between the two images are that the iPhone 4S is loaded with iOS 5 and has the aforementioned Verizon iPhone 4 antenna placement.
Additionally! Apple's Japanese website seemed to have jumped the gun on the iPhone 4S announcement. If you navigate to their website, you can see a placeholder for the iPhone 4S with a description that specifically says the iPhone 4S will launch on October 14th. That's right in line with previous rumors. Here's the screencap of Apple's Japanese website, which also mentions a new iPod nano!