Your address book data is found at ~/Library/Application Support/AddressBook. Just copy that folder over to the same location and you'll be good to go (just make sure address book isn't running).
Edit: Or you could just use Migration Assistant to copy all your user data over.
I'm not sure if Panther's Address Book had this (let alone earlier versions), but along with iCal, the Tiger version has a Back Up feature in the File menu. I find this to be extremely useful. 🙂