According to Boy Genius Report, all of AT&T's pre-order iPhones have been reserved as of 4:30pm EST. And if you placed an order any time after that, you might have a bit of a wait on your hands. Updated:
People who got their orders in after 4:30 are expected to get their phones any time between June 25th and July 5th, an awfully long time considering how much of an incredible pain it was to sign up for a phone today.
So far it seems like only phones at AT&T stores are sold out, so orders placed through the Apple Store and elsewhere should still hold up. We'll update if and when any official word comes through.
Updated: AT&T's official statement confirming the sellout:
"Because of the incredible interest in iPhone 4, today was the busiest online sales day in AT&T history. As of Tuesday afternoon, customers who preorder iPhone 4 moving forward will receive their device on June 25 or later, depending on when the order is placed. We'll email customers with confirmation once their order is placed, and again when it ships. In addition, we will have devices available on a first-come, first-serve basis in our stores beginning on June 24."
The other question is: what happens to all those people who placed orders using AT&T's pen and paper fail safe system? One tipster placed who placed his order at noon EST got this discouraging confirmation email at 5:45:
Note the "shipping on or after June 24th," which hints that what matters is when AT&T got around to processing your order, not when it was first logged. Then again, it could just be their stock email.
What a mess.
Update: The Apple Store has sold out as well. [BGR, Thanks Corey!]