Guide Google API V3

We have account on Google.
Sign in to Google Console. https://code.google.com/apis/console/.

Step1 : On API Project, we can create, edit, delete.


Step2: After create project, we need enable service which we need.


Step3: Create API Access

and we have a client API.


Step4:
Example to Analytics.
Now we add permission for service as google analytics.
add "email address" on step 3 as the user can access google analytics.

Step5:
Go to link below to get Google APIs Client Library for PHP.
http://code.google.com/p/google-api-php-client/
Note: More API about google analytics Google Analytics API Investigation