This article has been updated here: How to sync your Apple address book with Google contacts
The method below is obsolete but I have left it here for reference in case you are running an older version of OS X.
Here is how to access any of your Gmail contacts from the Apple OS X Address Book . I personally don’t think this is a great feature because I like to keep all my contacts in one place – Apple’s address book. But if you have contacts in your online gmail account and want them on your OSX address book, this might be handy.
1. Open your ‘Contacts’ App, and from the ‘File Menu’ select ‘Preferences’. Click on the blue @ symbol to bring up the Accounts Tab as below:
2. Click on the little + sign in the bottom left to add a new account, select ‘CardDAV’ and enter your gmail login details. For ‘server address’ enter ‘google.com’. Click ‘Create’.
3. Deselect ‘Mail’ because you just want to sync contacts here not your mail. Click ‘Create’ again.
Now if you open your contacts app, down the bottom there will be a new entry called ‘Google’. If you click on it you can see all your gmail contacts.