A Under "app/code/core/Mage/Catalog/Model/Config.php", add this value to the $options array: 'created_at' => Mage::helper('catalog')->__('Date')
B Under "app/code/core/mage/catalog/model/resource/eav/mysql4/product/collection.php", add this value to the $options array: $this->getSelect()->order("e.entity_id desc");
C Under "app/code/core/Mage/Catalog/Model/Config.php", add this value to the $options array: 'sort_by' => Mage::helper('catalog')->__('Date')
D It's not possible to sort products in the catalog by date.