If I understand you correctly, you want to know how to get things like the star for Favorites or the magnifying glass for Search. Is that correct?
To do it in code, use this UITabBarItem function:
- (id)initWithTabBarSystemItem:(UITabBarSystemItem)systemItem tag:(NSInteger)tag;
where systemItem is one of these:
UITabBarSystemItemMore
UITabBarSystemItemFavorites
UITabBarSystemItemFeatured
UITabBarSystemItemTopRated
UITabBarSystemItemRecents
UITabBarSystemItemContacts
UITabBarSystemItemHistory
UITabBarSystemItemBookmarks
UITabBarSystemItemSearch
UITabBarSystemItemDownloads
UITabBarSystemItemMostRecent
UITabBarSystemItemMostViewed
To do it in Interface Builder (which I don't use myself), add the UITabBar and then a UITabBaritem; then select the type of the bar item from Tab BarItem Attributes:BarItem in the Inspector.
Creating UITabBars is actually pretty complex. Read the documentation carefully and look at the tutorials. If you are confused, you are not alone. (And learn the difference betwen a UIToolbar (which let's the user take actions) and a UITabBar (which let's the user change what they are looking at or how the information is displayed.)
Note: Be very careful using the custom items. Do NOT, for example, use the Search icon to mean "show the same data but with a larger font size". Your application will be rejected if you do that.