[gb2world]

The easiest thing to do is to add it to skin1/common.js - then it will be available to any page that calls common.js - which I think may be every page on 4.1.x (if you do this, remove the <script> and </script>)

If you only want to call it on the category pages - you can add it to skin/1/customer/home.tpl with an if/than statement to only use it when you want it. If you add it to a template, be sure to surround it with {literal} and {/literal} tags.