On June 15 Apple and some select carriers began allowing customers to pre-order the iPhone 4 for delivery or pick-up on the official launch day, June 24.
The morning began with the online Apple Store in the UK and US going up and down while Apple appeared to attempt to solve stability problems but the online stores remained close to non-operational for the majority of the day.
The problem in the US has partly been blamed on AT&T servers collapsing under the load.
In the UK, although unlocked and SIM-free iPhones can be pre-ordered on the online Apple Store no carrier began accepting pre-orders or released subsidised handset pricing. Last week, Three and Orange in the UK confirmed that they would begin pre-orders starting June 15.
As the day began to end AT&T issued a statement to Engadget to confirm that it had sold out of all iPhone 4 models:
"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."
Currently Apple's US online store lists ship dates of June 24 for pre-ordering whilst the UK online store now shows pre-orders shipping by July 2.