如何按级别显示类别？

<?php
        //print_r($_category); exit;

        $Curr_cat_id = $_category->getEntityId();

        $children = Mage::getModel(\'catalog/category\')->getCategories($Curr_cat_id);

        if($children){

            foreach($children as $sub_cat)
            {
               $subCat = Mage::getModel(\'catalog/category\')->load($sub_cat->getId());

               ?>

                <a href=\"<?php echo $this->getUrl().$sub_cat->getRequestPath(); ?>\" >
                    <?php echo $sub_cat->getName(); ?>
                </a><br />

             <?php

            } // end of foreach

        } // end of if

        //else{

          // this is where i want the same level categories if in case there are no sub-categories and also the current category is not a main category.

        //}

    ?>