In iOS 6.0 and above you have some options:

• Use a UIWebView (the google maps rendering 'engine' is not present as before) to load the maps.google.com page

• Use the Google Maps iOS SDK (Best Option)

• Use MapBox and use similar topography rendering to google maps

With the official Google Maps iOS SDK you can actually add your own map to your app, so this is your best option. The docs have great detailed info on how to setup!