[Mr Happy]

By forum-link you mean a link back to the main home page?

If so that already exists. It's only a small image though at the moment which is

If you want you could add text beside it saying Home or something else.

To do this go to ACP -> Navigation / Breadcrumb Templates -> navbar
and you should find something like this near the bottom:

<div id="breadcrumb" class="breadcrumb">
<ul class="floatcontainer">
<li class="navbithome"><a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" />Home</a></li>

{vb:raw navbits.breadcrumb}
{vb:raw navbits.lastelement}
</ul>

and add Home where I have

Sorry if this isn't what your after. I don't fully understand you.