I think you are asking for post approval feature.
To enable it perform the following steps:
Administration Center » Core Features
Post Moderation (enable this option from here)
Administration Center » Permissions » Edit Profiles
Create a new profile in here and name it anything you like (Personally I prefer it named as "Approval")
Now, click on profile approval and set permissions for each group.
Post new topics, without requiring approval -- uncheck that options for those groups for which you want to activate the approval system when they create a new topic.
To see the unapproved posts see the moderation center of your forum.
Hope this helps you