Magento Sorting by category custom attribute

      $categories = Mage::getModel('catalog/category')->getCollection()
        ->addAttributeToFilter("show_on_home_page",1)
 ->addAttributeToSelect("name")
 ->addAttributeToSelect("description")
 ->addAttributeToSelect("catextra_description")
 ->addAttributeToSelect("catextra_order")
 ->addAttributeToSelect("thumbnail")
 ->addAttributeToSort('catextra_order', ASC);
       

Magento check If Home Page

if(Mage::getSingleton('cms/page')->getIdentifier() == 'home'  && Mage::app()->getFrontController()->getRequest()->getRouteName() == 'cms') :

endif;