Depends on how elaborate you want to be, but there are a few CiviCRM-related options. CiviCRM (www.civicrm.org) is a full featured constituent relationship management system that works with Drupal.

(1) CiviCRM Profiles. Trusted admins maintain the data, phone books are displayed to those who have permission to view. Permission cab be managed via drupal access control. You can also limit profiles to displaying just a certain CiviCRM group Docs

(2) Distributed CiviCRM. Different groups have different access to different records in the database, but if they have access they have full edit rights. This is accomplished via drupal access control and CiviCRM groups. You would only give people access to the groups of records you want them to have edit rights to. Docs