[B00MER]

<table border="0" cellspacing="5" cellpadding="0" width="100%"><Tr>

{section name=product loop=$f_products}

{if $smarty.section.product.index is div by 3}
  </tr><tr align="center" valign="top">
{/if}

{* Product stuff here *}

</td></tr></table>

{/section}

This is how I did it with the product listing same scenerio with the category list.