I was able to go to UPS website and use the primary # to track by reference a few days back. Mine says that deliver is for Friday the 21st. (I Ordered in the first hour of preorder on Apple.com)
Just a heads up for some of us: I purchased through AT&T @ 12:48AM PDT and had nothing on the ATT website except processing until yesterday. It switched to shipped w/o any info. Today it shows tracking from UPS and I confirmed that I will be receiving it on 9/21. So check with UPS.
I've been tracking my iPhone using the Shipment Reference method, but I just received the official email from Apple saying that my iPhone shipped and is on it's way. My iPhone originally shipped out on Sept 16 and is scheduled to be delivered by 10:30 AM tomorrow Friday, Sept 21st!! So excited to finally get my hands on the iPhone 5 as I'm upgrading from an iPhone 4 with a cracked screen and a home button that is fading fast.