<?php
function email_author_about_publishing() {
	global $wpdb, $post_ID, $post_type;

	$users = $wpdb->get_results( "SELECT ID FROM $wpdb->usermeta WHERE meta_key = 'wp_user_level' && meta_value > 0" );
	$post = $wpdb->get_row("SELECT post_author, post_title, post_type FROM $wpdb->posts WHERE ID =" . $post_ID);

	$authordata = get_userdata( $post->post_author );

	$blogname = get_settings( "blogname" );
	$subject = "Your post has been published!";

	$text ="Ciao  ". $authordata->user_nicename . ",";
	$text = $text . "\n\nYour post  " . $post->post_title." has been published.";
	$text = $text . "\n\nYou can read it here: " . get_permalink( $post_ID );mail( $authordata->user_email,
$subject,$text,"From: " . $blogname . " <" . get_settings( "admin_email" ) . ">" );}

if ( $post_type == get_post_type('listing'))

 add_action('publish_post', 'email_author_about_publishing');
?>