If you work with drafts from students and then publish, here’s a bit of code for functions.php that will send the author an e-mail once the post is live.

function wpr_authorNotification($post_id) {
   $post = get_post($post_id);
   $author = get_userdata($post->post_author);

   $message = "
      Hi ".$author->display_name.",
      Your post, ".$post->post_title." has just been published. Well done!
   ";
   wp_mail($author->user_email, "Your article is online", $message);
}
add_action('publish_post', 'wpr_authorNotification');

SOURCE: WPRecipes.(via Cats Who Code)