Sort By Date Module Magento (Descending Ordering)
<catalog_category_default translate="label">
<reference name="product_list_toolbar">
<action method="setDefaultDirection" ifconfig="sortbydate/general/sorting_desc"><dir>desc</dir></action>
</reference>
</catalog_category_default>
<catalog_category_layered translate="label">
<reference name="product_list_toolbar">
<action method="setDefaultDirection" ifconfig="sortbydate/general/sorting_desc"><dir>desc</dir></action>
</reference>
</catalog_category_layered>