Yes it's possible. You can use interface builder to add a UITabBar to whatever view you want. The view controller for the view should then implement the protocol UITabBarControllerDelegate to handle selections of tab bar items.
It's worth having a look at the template tab bar project that you can create in XCode to understand this. The view containing the tab bar is owned by the view controller - it's this view that gets added to the window in the application delegate -
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// Add the tab bar controller's current view as a subview of the window
[window addSubview:tabBarController.view];
}