Magento Sale icon if special price available

Open app/design/frontend/YourPackage/YourTheme/template/catalog/list.phtml Find (around line 96)

<a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" class="product-image">

<img src="<?php echo $this->helper('catalog/image')->init($_product, 'small_image')->resize(135); ?>" width="135" height="135" alt="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" />

</a>

change to

<a href="<?php echo $_product->getProductUrl() ?>" title="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" class="product-image">

<img src="<?php echo $this->helper('catalog/image')->init($_product, 'small_image')->resize(135); ?>" width="135" height="135" alt="<?php echo $this->stripTags($this->getImageLabel($_product, 'small_image'), null, true) ?>" />

<?php 

    // Get the Special Price

    $specialprice = Mage::getModel('catalog/product')->load($_product->getId())->getSpecialPrice(); 

    // Get the Special Price FROM date

    $specialPriceFromDate = Mage::getModel('catalog/product')->load($_product->getId())->getSpecialFromDate();

    // Get the Special Price TO date

    $specialPriceToDate = Mage::getModel('catalog/product')->load($_product->getId())->getSpecialToDate();

    // Get Current date

    $today =  time();

    if ($specialprice):

        if($today >= strtotime( $specialPriceFromDate) && $today <= strtotime($specialPriceToDate) || $today >= strtotime( $specialPriceFromDate) && is_null($specialPriceToDate)):

?>

        <img src="path/to/sale-icon.png" width="50" height="50" class="onsaleicon" />

<?php  

        endif;

    endif;

?>

</a>

Next open style.css (skin/frontend/YourPackage/YourTheme/css/style.css)Find

.products-grid .product-image { display:block; width:135px; height:135px; margin:0 0 10px; }

change to

.products-grid .product-image { display:block; width:135px; height:135px; margin:0 0 10px; position:relative;}

Below this add

.onsaleicon{position:absolute; top:0; right:0;}