Preview what your website looks like on an iPhone.
About Our iPhone Web Previewer
Even though a standard iPhone 4/4s has a native resolutuon of 960 X 640, the iPhone's Safari browser still scales websites down proportionately to fit within the screen frame. So our previewer is showing the screen real estate in a 480 x 320 frame, which actually is the exact resolution of an iPhone 3. You could test this if you have both the iPhone 3 and 4, next to each other. If you bring up the same site, they will proportionaly display at the same size. The difference is that with the iPhone 4's Retina Display, the pixel sharpness displays the type and graphics with more clarity.