wp-comments-by-post-type.php

<?php
/*
Plugin Name: WP Comments by Post Type
Description: Enables PHP Developers to filter the comment admin at edit-comments.php by post type using a $_GET parameter. Use the "comment_admin_menu_post_types" hook to filter the array of post_type names to limit the admin menus that get a "Comments" option.
Version: 0.1
Author: Mike Schinkel
Author URI: http://mikeschinkel.com/custom-wordpress/plugins
*/
add_action('query', 'hook_to_filter_comment_admin_by_post_type');
function hook_to_filter_comment_admin_by_post_type($sql) {
	global $pagenow;
	if ($pagenow=='edit-comments.php' &&
			!empty($_GET['post_type']) && 
			post_type_exists($_GET['post_type']) &&
			preg_match('#^SELECT \* FROM wp_comments c#',$sql)) {
		$sql = str_replace(' WHERE '," WHERE p.post_type='{$_GET['post_type']}' AND ",$sql);
	}
	return $sql;
}
add_action('admin_menu', 'hook_to_add_comment_admin_menu_option_for_each_post_type');
function hook_to_add_comment_admin_menu_option_for_each_post_type() {
	$post_types = apply_filters('comment_admin_menu_post_types',get_post_types(array('public'=>true,'show_ui'=>true)));
	foreach($post_types as $post_type) {
		if ($post_type!='post') // Don't do for Posts, they already gota one! 
			add_submenu_page("edit.php?post_type={$post_type}",__('Comments'),__('Comments'),'moderate_comments',"edit-comments.php?post_type={$post_type}" );
	}
}