If it's still under AppleCare then they would more than likely replace it with a refurb 3GSjust recently my 3gs has stopped working, and since the release of the iphone 5 I heard the 3gs is discontinued. is this true? will my warranty replace it with an iphone 4?
Actually Apple is not fulfilling any orders for the 3GS for Genius Bar replacements...they are upgrading you to the iPhone 4.
Don't get the original posters hopes up that there is a 100% change of getting an iPhone 4!