Hi Marco. I'm no expert at this (one or two will be along shortly...) but I've found that in playing around with PHP and CSS I've been able to do a lot more than I thought I would.
The code you've posted would display not just the forum names, but most of your front-page info. I'm wondering if putting the forum names in a < div > with a class name you've defined in the stylesheet to format the fornt, placing, width, etc., would do it. This is a rough ide from my front-page;
<div id="my_side_bar">
<?php if ( bb_forums() ) : ?>
<table id="forumlist">
<?php while ( bb_forum() ) : ?>
<tr<?php bb_forum_class(); ?>>
<td><a href="<?php forum_link(); ?>"><?php forum_name(); ?></a><br />
</td></tr>
<?php endwhile; ?>
</table>
<?php endif; // bb_forums() ?>
The table definition could probably be removed too, and it should(?) give a list of links with just forum names. Blind leading the blind here, but it might give you some ideas.