From Headlight Software:
Transfer contacts from one iPhone's address book to another iPhone with just a few clicks.
Why try and type in all the name, phone, email, address information to add a contact to your iPhone if someone else with an iPhone already has it. Make a clone copy of theirs with ContactClone.
Simply start ContactClone on the two or more iPhones (or iPod touches) when you're in the same wireless network. Pick the contacts from your address book you want to share; or browse the contacts the other person is sharing from their iPhone.
Just a touch of the person's name will add them into your address book. Including all information, email, phone number, even the photo. A perfect clone.
A Key lets you only share your contacts with the people you want, and you can set to keep some things private (photos, notes, etc.)