This will get you started - it may need adjustments for different cart versions
Code:
{if $product.manufacturer ne ""}
<a href="manufacturers.php?manufacturerid={$product.manufacturerid}"><img src="image.php?id={$product.manufacturerid}&type=M" alt="{$manufacturer}" /></a> <a href="manufacturers.php?manufacturerid={$product.manufacturerid}">See All Products</a>
{/if}