Speedboxer

The Comment Approval Notification plugin will send an email to the comment author when you approve their comment. The email sent is fully customizable, with shortcodes, through a settings page.
Please note that this plugin has only been tested with PHP 5.2.x.
A full list of available shortcodes is available <a href="http://mattsblog.ca/plugins/comment-approval-notification/#shortcodes" title="Available Shortcodes" rel="nofollow ugc">here</a>.

Comment Approval Notification

Sends an email to the comment author when their comment gets approved (only if it's held for moderation).

tyfdesign

When activated, this plugin: 
1. Closes comments and pings on all existing public content (posts, pages, and custom post types). 
2. Sets WordPress defaults to disallow new comments and pings on all future content. 
3. Ensures that newly created or updated posts remain closed to comments. 
4. Hides the default Comments menu in the admin sidebar when enabled. 
5. Provides a simple Settings page with a single Activate / Deactivate button to toggle behavior.
When deactivated, the plugin restores the default WordPress discussion settings without reopening previously closed comments.
Created by TYF Design.

Do Not Allow Comments Everywhere

A lightweight plugin that globally disables comments and pings across all WordPress content - past and future.

Comment Approval Notification vs Do Not Allow Comments Everywhere