The SitePoint PHP blog has posted the first two parts of a "Social Network Authentication" series looking at connecting your application with social network systems. In these first two posts they help you get things set up to connect to the remote systems and create an actual connection to Google+.
Almost every website which contains a log in option, also contains ways to log in through different social networks. In this series of articles, we will take a look at how we can make sure that our visitor can log in through Google+ and eventually other networks like Twitter and Facebook. In the final article, we will have a close look at how we can make sure users don't have different accounts due to the fact that they used different social networks. We will create a framework agnostic package which can easily handle users from different social networks. In this part, we will have a look at our basic setup.
The first tutorial helps you get things all set up and takes the first steps in making the "SocialLogin" package. In the second tutorial they use this package structure to create a Google+ specific instance, making the OAuth connection as simple as calling a method, loading a URL and handling the response.