Navigate to
app/design/frontend/<package_name>/<theme_name>/template/catalog/product/list.phtml
else copy this file from base/default theme to your theme
Goto this line
<h2 class="product-name"><a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $_productNameStripped; ?>"><?php echo $_helper->productAttribute($_product, $_product->getName() , 'name'); ?></a></h2>
Add your condition before it