Who would want to use CardDAV-Sync or CalDAV-Sync with a Google-Account? Every device should do that natively. However if you want to use CalDAV-Sync to sync your Google Calendar enter the following data.
- Server URL: www.google.com/calendar/dav/
- Use SSL: leave checked
- Username: your Google Mail address
- Password: your Google password
alternatively open this link from your phone's browser.
Currently one-way-sync only. Uploading events seems to be broken (go to http://code.google.com/p/google-caldav-issues/issues/detail?id=26 to see why).
By default only your main calendar is enabled for synchronization via CalDAV. To sync other calendars go to https://www.google.com/calendar/iphoneselect and enable them. If you already created an account go to "Edit calendars to sync" in the account settings to update the calendars.
CardDAV-Sync is untested. Does Google support CardDAV at all?