Adding help information to custom post edit page

Try this:

function options_instructions_example() {
    global $my_admin_page;
    $screen = get_current_screen();

    if ( is_admin() && ($screen->id == 'custom_post_type_name') ) {

        function add_content_after_editor() {
            global $post;
            $id = $post->ID;
            echo '<div class="postbox" style="background:#0074a2;color:#fff;margin-top:20px;"><div class="inside">';
            echo 'Instructions go here.';
            echo '</div></div>';
        }
        add_action( 'edit_form_after_title', 'add_content_after_editor' );
    }
}
add_action( 'admin_notices', 'options_instructions_example' );

It will result in something that looks similar to this:
http://i.stack.imgur.com/5rU66.png