Really cool way to create custom UITabBar for iPhone app?
There's a project on github called BCTabBarController that aims to mimic the tab bar used in Twitter for iPhone. It's got some of the things you're looking for, and should give a great starting point.
Both of these are good answers, but both libraries have problems: BCTabBarController doesn't know how to create the "blue" highlighted version of a tab bar icon; and iDevRecipies doesn't send events to child viewcontrollers nor resize the navigation bar on rotate.
Be warned: custom nav bars are a lot of trial-and-error debugging (as I have found).
Simply use a UIView with TabBar width and height.Add custom background image and custom buttons on the view.Set the fileowner of the view as AppDelegate.Now you can simply connect the IBActions with the buttons.The Custom view can be placed over the tabbar by addSubView to the TabBar controller's view.You can switch between viewcontrollers by using the setSelectedIndex method of tableviewcontroller in the button action.