been watching an app for a month or so and the latest update now has it working with zimbra
https://market.android.com/details?i...s.carddav.sync
you'll also need the editor app to edit your contacts after sync
https://market.android.com/details?i...droid.contacts
the author has a paid version of the same app to support the development, so consider this option if you are happy with the product.
now, all i need is a caldav sync for android that integrates into the default calendar and i'm set to live on MY cloud.