Bulk edit Address Book data

Regrettably, Address Book doesn’t include a bulk-edit feature, but there’s a way to use Apple’s TextEdit to solve this one. Try this:

Start by launching Address Book and choosing File -> Export -> Address Book Archive. This will create a backup of all your contacts. Should something go wrong, you can always return to this backup.

via Bulk edit Address Book data | Mac 911 | Macworld.