How can I restrict access to MMC snap-ins?

Start Active Directory Users and Computers snap-in (Start - Programs - Administrative Tools - Active Directory Users and Computers)

Right click on the domain or OU with the Group Policy set and select Properties

Select the Group Policies tab

Select the Group Policy you wish to change and click Edit

Move to User ConfigurationAdministrative TemplatesWindows ComponentsMicrosoft Management Console

Double click 'Restrict Users to the explicitly permitted list of snap-ins'

Set to Enabled or Disabled.

You can then move to "Restricted/Permitted snap-ins" and enable or disable specific snap-ins