To add a contact to your address book using Yahoo! Messenger:
When you add a contact to your Messenger List, the contact is automatically added to your Yahoo! Address Book.
Please Note: From within Yahoo! Address Book, when you add a contact with the Add Contact form, you can add the contact to your Messenger List, too, by entering the person's Yahoo! ID in the text field provided and clicking the checkbox labeled "Add this person to my Messenger List."
Where's the Contact Customer Care button? With so many improvements to Messenger since the version you're using (lots more features and reliability), we figured you're ready to move up. So get your upgrade and with the new version, rest assured if you have questions, you’ll find that friendly button on its help pages.