Drupal - Address book

Contact Manager is a module to manage contacts over different mediums.

Address book module contains a simple addressbook.

Drupal contact importer module lets users import contacts from various third party services such as facebook, myspace, gmail, yahoo, friendfeed, twitter, and numerous other services using the OpenInviter library.

LDAP directory provides an "Address book" feature. It searches an LDAP server for records and allow people to view the returned set. My company use it as a Company Directory. It is badly in need of some good Documentation and like everything dealing with ldap it is really hard to setup and get working.

LDAP contact manager provides the ability of access to LDAP directories from inside Drupal, perform full-text or advanced search and even manage (add, edit) entries.
The next goal of the project is to read the LDAP schemas used for the objects to create a cck-like way to manage/display them, and maybe integration with the Views module too.

CiviCRM is web-based, open source, internationalized, free open source constituent relationship management solution. CiviCRM is an actively maintained project with an installed base of over 5,000 organizations. It is specifically designed to run inside of your Drupal site(s).