How to show recently viewed product on product description page

<block type="reports/product_viewed" name="reports.product.viewed" as="recently_viewed" template="reports/product_viewed.phtml"> 

<action method="setColumnCount">

<columns>4</columns>

</action>

  <action method="setItemLimit">

<type>recently_viewed</type><limit>4</limit>

</action>           

</block>

in the template file: catalog/product/view.phtml:

<?php echo $this->getChildHtml('recently_viewed') ?>