Реализуйте следующий код в вашем appDidFinishL. функция
не будет утечки
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// Override point for customization after app launch
NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:0 diskCapacity:0 diskPath:nil];
[NSURLCache setSharedURLCache:sharedCache];
[sharedCache release];
[window addSubview:[navigationController view]];
[window makeKeyAndVisible];
}