function widget_mytheme_stichwort() {
?>
<h2>Stichwörter</h2>
<ul class="noarrow"><li>
   <?php wp_tag_cloud('smallest=8&largest=22&unit=pt&number=70&format=flat&orderby=name&order=ASC'); ?></li>    
</ul>
<?php
}
if ( function_exists('register_sidebar_widget') )
    register_sidebar_widget(__('Stichwort'), 'widget_mytheme_stichwort');