Apple released an official statement this morning that included some juicy details on how many iPhone 4s they sold on the first day of pre-ordering, which was yesterday. They also apologized for the bad experience customers had toward the beginning of the day when both AT&T and Apple's servers crashed, preventing anyone for pre-ordering the phones for quite a while.

Apple reports they sold over 600,000 iPhone 4s in that one day yesterday, which is the most pre-orders they have ever received in one day. It is also ten times more iPhone 3GS pre-orders sold in the first day. So much, that they officially sold out of pre-orders last night. Now anyone who pre-orders their iPhone 4 will have to wait until July 2nd to receive it at their door or at a local Apple Store.

Here's Apple's entire press release:

Yesterday Apple and its carrier partners took pre-orders for more than 600,000 of Apple’s new iPhone 4. It was the largest number of pre-orders Apple has ever taken in a single day and was far higher than we anticipated, resulting in many order and approval system malfunctions. Many customers were turned away or abandoned the process in frustration. We apologize to everyone who encountered difficulties, and hope that they will try again or visit an Apple or carrier store once the iPhone 4 is in stock.

Update (2:55p ET): Delivery dates for pre-orders have been pushed back even further this morning to July 14th.