This is great news!  Google Contacts will now sync with the Snow Leopard Address Book (even without an iPhone)!

To get this to work:

1. BACKUP ALL DATA – both Google Contacts and Address Book contacts.
2. In Address Book, open Preferences (⌘+,).  Under the Accounts tab, check the "synchronize with Google box."  Enter your google login and password.
3. In the menu bar, click on the sync icon, and choose "sync now."  (If you don't see the sync icon in the menu bar, open iSync.  Open Preferences (⌘+,).  Be sure the "Show Status in Menu Bar" box is checked.

Boom, you are set!  Now your address book will update automatically (though I'm not sure how often).