Something

function theme_user_list_menu($items) {
              theme('add_style', drupal_get_path('module', 'user_list') .'/user_list.css');
              foreach ($items as $item) {
                      $link =  str_replace('&lt;em&gt;', '<em>', (l(t($item['title']), $item['path'])));
                      $link =  str_replace('&lt;/em&gt;', '</em>', $link);
                      $output .= '  <li class="leaf' . ($item['active'] ? ' active' : '') . '">' .$link. "</li>\n";
              }
             
              return "<div class=\"menu user_list_menu\">\n<ul>\n" . $output . '</ul></div>';
      }