9to5Mac is reporting that insiders have told them that Apple is expecting to announce sales of five million iPhones at MacWorld 2008. Up to one million of those will have been sold in Europe since they went on sale in early November in the UK and Germany (and late November in France).
With Apple stating that its goal was to sell 10 million iPhones in 2008, such an announcement would be a clear indication that Apple will not only meet that goal but significantly exceed it (especially if a 16GB version and a 3G version follow later in the year).
If these numbers do turn out to be true, it would indicate that demand for the iPhone has suffered no slowdown but gained significant momentum instead. It was only in September that Apple announced that it had sold its first million iPhones.