If you mean the difference it's quit alot. The iPhone 4 includes a retina screen, a new design and style, it shoots HD videos and pictures and it has flash. It almost the same as the iPhone 3GS...
iPhone 4 has a range of improvements including high resolution screen, gyroscope, improved processor, 512MB RAM, 5 megapixel camera with flash and a front facing camera for video calling. -----------...