Index: pluggable.php
===================================================================
--- pluggable.php	(revision 23176)
+++ pluggable.php	(working copy)
@@ -1070,7 +1070,10 @@
 	$subject = apply_filters('comment_notification_subject', $subject, $comment_id);
 	$message_headers = apply_filters('comment_notification_headers', $message_headers, $comment_id);
 
-	@wp_mail( $author->user_email, $subject, $notify_message, $message_headers );
+	$email_to = apply_filters( 'comment_notification_email_to', array( $author->user_email ) );
+	
+	foreach ( $email_to as $email )
+		@wp_mail($email, $subject, $notify_message, $message_headers);
 
 	return true;
 }