If you preordered earlier than those getting prepared now, then I'd contact Apple, AT&T (if US-based), and possibly your credit card company. One of the three may be having issues.
Two months back, I ordered a pair of speakers for my iPhone and an iPad accessory. Somehow, the way Apple sent the charge through, the card company flagged it as possibly fraudulent--there was plenty left on the credit limit and the bill wasn't overdue, it was 100% Apple's fault for sending the same charge more than once (and the charge didn't match either item alone, much less both). Apple didn't notify me in any way; I found out about it a day later when the two "ships next day" items hadn't been sent. I hadn't checked my voicemail the previous night; turns out the card company had called me with the fraud alert. I had to call them and straighten that out, then call Apple because now they wouldn't let that card be used through the site.
Needless to say, I'm watching all three companies involved to see which one botches this particular transaction...