ZillowMe4AddressBook is a Mac OS X Address Book plugin that allows Zillow lookups via a contextual menu item. After you install, just restart the Address Book application, and you will have a "Zillow Me" option for each address you click on. That address will then be looked up in Zillow in FireFox.
Mac OS X Application, Freeware, $0.00, released 2007-01-15
Initial release.