How to set iPhone tab bar icon in code?

yourViewController.tabBarItem = [[UITabBarItem alloc]
initWithTitle:NSLocalizedString(@"Name", @"Name")
image:[UIImage imageNamed:@"tab_ yourViewController.png"]
tag:3];

The viewControllers are added to the tab bar, so the image and names should be set before the tab bar becomes visible (appDelegate if they are there on app start for instance). After that, you could use the above code to change the icon and text from the loadView or viewDidAppear within that viewController.