The Apple Store is down ahead of the iPhone 5C pre-orders, Apple were due to start taking pre-orders on the device at 12AM Pacific Time, and the store should be back online shortly.
The iPhone 5C will go up for pre-order shortly, and it will launch in Apple stores and with the various mobile carriers, next Friday the 20th of September.
The iPhone 5S will go on sale next Friday the 20th of September, although Apple are not taking pre-orders on the iPhone 5S. Apple are also not allowing the mobile carriers to take pre-orders on the iPhone 5S.
We presume this is being done to boost pre-order sales of the new iPhone 5C. I have spoken to a number of mobile carriers here in the UK, and have been told that they are not allowed to take pre-orders on the iPhone 5S, although a number of them are creating lists of customers who want the device.
Source Apple