Depending what template your using basically within skin1/customer/head.tpl
Look for this:
<a href="{$catalogs.customer}/
home.php"><img src="{$SkinDir}/abeez_sources/sky_blue/images/yourlogo.png" title="Your" /></a>
Replacing the red highlighted with say:
home.php?cat=4 assuming you have no SEO Mods insatlled.
Is this what you mean