Shakir,can call using xml.Follow below step for this work
Step1: Goto app/design/frontend/yourpackage/youtemplate/layout/catalog.xml
<catalog_product_view>
.......
<reference name="left">
<block type="core/template" name="catalog.product.leftcoupn" before="-" template="catalog/product/view/showcoupon.phtml"/>
</reference>
</catalog_product_view>
Step then add an file under app/design/frontend/yourpackage/youtemplate/template/catalog/product/viewshowcoupon.phtml
and
Code of showcoupon.phtml is
<?php
/** @var $collection Mage_SalesRule_Model_Mysql4_Rule_Collection */
$collection = Mage::getModel('salesrule/rule')
->getResourceCollection()->addFieldTOFilter('is_active',1);
$collection->addWebsitesToResult();
foreach($collection as $each){
echo "<pre>";
//print_r($each);
echo "</pre>";
echo $each->getName().'<br/>';
echo $each->getCoupon_code().'<br/>';
echo $each->getFromDate().'<br/>';
echo $each->getToDate().'<br/>';
echo $each->getIsActive().'<br/>';
}
?>