Advanced Forum permissions
The Forum Access module works in Drupal 7, so I'll stick to this for now.


  This module changes your forum administration page to allow you to set forums private. You can control what user roles can view, edit, delete, and post to each forum. You can also give each forum a list of users who have administrative access on that forum (AKA moderators).
  
  This module requires the ACL module in order to function. The D7 version also requires the Chain Menu Access API module.