Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 18407)
+++ wp-includes/comment.php	(working copy)
@@ -1392,7 +1395,8 @@
 			$status = '1';
 			if ( get_option('comments_notify') ) {
 				$comment = get_comment($comment_id);
-				wp_notify_postauthor($comment_id, $comment->comment_type);
+				if( 0 == $comment->comment_approved )
+					wp_notify_postauthor($comment_id, $comment->comment_type);
 			}
 			break;
 		case 'spam':