[Victor D]

Something like this:

{*
$Id: categories.tpl,v 1.33 2008/11/06 16:53:53 max Exp $
vim: set ts=2 sw=2 sts=2 et:
*}
{capture name=menu}
    {if $active_modules.Fancy_Categories}
          {include file="modules/Fancy_Categories/categories.tpl"}
          {assign var="additional_class" value="menu-fancy-categories-list"}
    {else}
        {assign var=thiscat value=$cat}
        {assign var=par value=0}
        {foreach from=$categories item=cats}
            {assign var=Mcatid value=$cats.categoryid}
            {foreach from=$allsubcategories.$Mcatid item=subb}
                  {if $subb.categoryid eq $thiscat}
                    {assign var=par value=$subb.parentid}
                  {/if}
            {/foreach}
        {/foreach}
          <ul>
        {foreach from=$categories_menu_list item=c}
<li><a {if $c.categoryid eq $thiscat}class="selcat"{/if} href="home.php?cat={$c.categoryid}" title="{$c.category|escape}">{$c.category}</a></li>
            {if $c.categoryid eq $par}
                {foreach from=$allsubcategories.$par item=sub}
                    {if $sub.parentid eq $c.categoryid}
                        <a href="home.php?cat={$sub.categoryid}" class="subMenuItem {if $sub.categoryid eq $thiscat}selcat{/if}">-{$sub.category}</a>
                    {/if}
                {/foreach}
            {/if}
            {foreach from=$allcategories item=cat}
                {if $cat.parentid eq $c.categoryid}
                    <a href="home.php?cat={$cat.categoryid}" class="subMenuItem {if $cat.categoryid eq $thiscat}selcat{/if}">-{$cat.category}</a>
                {/if}
            {/foreach}
        {/foreach}
          </ul>
          {assign var="additional_class" value="menu-categories-list"}
    {/if}
{/capture}
{include file="customer/menu_dialog.tpl" title=$lng.lbl_categories content=$smarty.capture.menu}

also add this to you main.css

.menu-categories-list ul li a.selcat{font-weight:bold}