[kube]

locate in your skin1.css the selector .ProductBorder

and change to...

.ProductBorder {
border:0;
}

Or if you're keen, and you want cleaner code, remove it all together from the relevant .tpl and then remove the .ProductBorder from skin1.css as it doesn't serve any function. But if you're unsure and may want to use it in future, keep it to border:0