iPhone Screen Resolution

iPhone Screen Resolution for iPhone 4S & 4 is 960×640 pixels previous iPhones have is 480×320

iPhone 4S & 4 screen resolution & pixel density
 

iPhone 4 has a screen resolution of 960×640 pixels, which is twice that of the prior iPhone models
The iPhone 4 also has a much higher pixel density than it’s predecessors, displaying 326ppi (pixels per inch).
 

Original iPhone, iPhone 3G, iPhone 3GS PPI & screen resolution
 

iPhone 2G, 3G, and 3GS screen resolution is 480×320 pixelsThe iPhone 2G, iPhone 3G, and iPhone 3GS has a display of 163ppi (ppi is pixels per inch whereas dpi is dots per inch).

For web Designer and Developer the iPhone Screen resolution was a key aspect in this development process. The actual pixel density differs on the iPhone models as well, which will effect the appearance of interface elements and graphics for websites and iPhone applications. 

yes knowing the resolution and PPI should not be limited to developers, it dramatically effects the graphic and picture quality of any user experience with the device.