屏幕分辨率和帧大小?

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    MyController *tempController = [[MyController alloc] init];
    [[tempController view] setFrame:CGRectMake(0.0,20.0,320.0,460.0)];
    [self setMyController:tempController];
    [tempController release];
    ...

iPhone 3\u sim卡、iPhone 4\u sim卡和iPhone 4\u设备的整个屏幕都会出现这种情况?我有点期待iPhone4的尺寸会翻倍,有没有某种自动应用程序缩放(翻倍)的功能,如果有,你如何设置/更改?

干杯,加里