Been trying since 3am EDT.
FINALLY got it to go through on Apple.com. Tried the Apple Store app, AT&T upgrade app, and AT&T.com. Apple.com was the only one that worked.
Got myself a 64G black and my wife a 16G white.
VERY excited to move from the 3GS to the 4S!!!
And for those curious, I had to submit two separate orders. Got E-Mail confirmation (with order number) for both. I was not able to modify the shipping address. It's shipping to the billing address on our wireless bill. We kept unlimited data. Delivery date is still listed as 10/14.
I am AT&T premier.
Hope that info helps someone.