remove-widget-titles.php

<?php
/*
Plugin Name: Remove Widget Titles
Plugin URI: http://scratch99.com/wordpress/plugins/remove-widget-titles/
Description: Removes the title from any widget that has a title starting with the "!" character.
Version: 1.0
Date: 23 November 2011
Author: Stephen Cronin
Author URI: http://www.scratch99.com/
   
   Copyright 2011 Stephen Cronin (email: sjc@scratch99.com)

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

// Add the filter and function, returning the widget title only if the first character is not "!"
add_filter( 'widget_title', 'remove_widget_title' );
function remove_widget_title( $widget_title ) {
	if ( substr ( $widget_title, 0, 1 ) == '!' )
		return;
	else 
		return ( $widget_title );
}

// What, you were expecting more? 

?>