PHP back end, Android client and G+ auth

[Jon Robinson]

Hey, 

Forgive me if this is not the correct place to be asking this question. 

I am trying to use google plus as a means of authentication between a PHP backend server and Android client. I have the Google plus sign in working on the latter (i.e. I have the access token), and can see (from various websites) how I might set up g+ with PHP but I cannot for the life of me work out how to get the two working in tandem. 

I suppose, getting to the crux of it, I am really after an example with the Android client and PHP server so I can pull it apart and understand how it works. Does anyone know of a good tutorial/ example along these lines? I have looked here, there and everywhere on the net to no avail. The closest I have found is Google's own PhotoHunt sample app, but unfortunately the PHP implementation is listed as 'coming soon'.

Thanks,