[gb2world]

You can define styles to overwite the skin1.css when you need to. You can have your default style is skin1.css, then for categories where you want to change it, add css to override it in home.tpl. You could add something like this before </head>:

<style type="text/css">
<!--
{if $current_category.categoryid eq 123}
 #header {background: #ffffff url(images/neon_lights/head_bg_123.gif) repeat-x 1px top;}
{/if}
{if $current_category.categoryid eq 456}
 #header {background: #ffffff url(images/neon_lights/head_bg_456.gif) repeat-x 1px top;}
{/if}

-->
 </style>