Google provides a lot of APIs to integrate with their services. There is a library they provide that you can use to easily integrate with those apis using Objective-C. In this video I show you how to get started with the library. This process is sure to work with Xcode 4+.
Here are the Google-provided instructions: http://code.google.com/p/google-api-objectivec-client/wiki/BuildingTheLibrary
I hope you enjoy this video and as always, be sure to subscribe and share this with others! :D