I was able to preorder a 6 (64gb) from AT&T at about 3:10AM and then I went ahead and preordered from Apple at 3:50AM when it finally decided to work. It's for the same line and I received confirmation emails for both of them.
So AT&T will automatically cancel my order from them? Is it possible to get two iPhones for the same line?
I made the same mistake. Ordered from AT&T, then apple. I got an at&t confirmation though. The AT&T site has a button to cancel the preorder, but it doesn't appear to work. My apple.com order went through as well, so now I'm on hold with AT&T canceling my order with them.