phonegap ios how release

phonegap ios how when released how to configure my page size is now released 640 * 980, and then I tested with iphone 4, iphone screen to screen in the expanded, iphone is 320 * 480 resolution display, how can I Let iphone with 640 * 960 resolution to open the program, I use Xcode4.3.1, how, heroes teach me step by step, be grateful