This is the official Apple iPhone 4 User Guide in English provided from the manufacturer. If you are looking for detailed technical specifications, please see our Specs page.
The iPhone 4 is now boxier, with the rear side now flat, instead of rounded. It will keep the 3.5-inch display diagonal, but will quadruple the pixels to 640x960, making it the highest-resolution screen on a smartphone to date. Apple actually calls the new screen Retina Display, because it shows 326 pixels per inch, while the human eye can only distinguish around 300 ppi. In addition, the screen will utilize the LCD IPS technology (same as in the iPad). The other new stuff includes a front-facing video call camera, 5MP main camera lens with LED flash and 720p HD video recording, Micro-SIM slot, instead of ordinary SIM, a secondary mic for noise-cancellation and a lot of other new features.