magento-browse-by-attribute
Magento Browse by Attribute Extension
Attributes Dropdown List
To display a dropdown with manufacturers, add the following xml:
<block type="browseby/attribute_navigation" name="browseby.manufacturer" template="browseby/attribute/dropdown.phtml">
<action method="setBrowseAttribute"><attribute>manufacturer</attribute></action>
<action method="setLabel"><label>Brands</label></action>
</block>