There's really no need to be rude to the Original Poster. Yes, this question has been asked many times before, but so has most questions posted.
While its possible that an update to the iPhone will be released before 2009, it is highly unlikely. There would be hundreds of thousands of angry customers if an updated iPhone is released, all the people that have just purchased an iPhone on EU iDay will be very angry with Apple.
Though, saying that, it is possible that Apple will introduce a 16GB model along side the 8GB model. We'll all just have to wait and see.