Exploring Google Maps for iOS is a free course covering everything from adding a simple map, to using geocoding and directions, to incorporating Street View in iOS. You'll end up with a working sample application and gain the knowledge you need to build your own amazing Google Maps-based apps. Learn from videos, sample code, and Xcode-based coding challenges.
Check out the introduction video below, and then head over to Code School to get started with their interactive course!
You can also read our official developer documentation and reference docs at https://developers.google.com/maps/documentation/ios/.