Whilst there was never really any concerns that Apples new iPhone would not be a worldwide success, even they have been taken aback by the pre release demand for their flagship phone. Orders for the new iPhone have exceeded 2 million within 24 hours. To put the figure in context, that is more than twice the amount of orders for the iPhone 4s on its first day.
It also seems likely that initial demand is ahead of supply so some pre order customers will receive their iPhones in October. The iPhone 5 will go on sale in the US on September 21st and worldwide the following Friday and is expected to sell upwards of 58 million units.