install full module and place following code in product_info.php
<?php
// DANIEL: begin - show related products
$attributes = "select pop_products_id_slave, products_name, products_price, products_tax_class_id, products_image from " . TABLE_PRODUCTS_OPTIONS_PRODUCTS . ", " . TABLE_PRODUCTS_DESCRIPTION . " pa, ". TABLE_PRODUCTS . " pb WHERE pop_products_id_slave = pa.products_id and pa.products_id=pb.products_id and language_id = '" . (int)$languages_id . "' and pop_products_id_master = '".$HTTP_GET_VARS['products_id']."' and products_status=1 order by pop_order_id, pop_id";
$attribute_query = tep_db_query($attributes);
echo '<tr><td><table class="productlisting" border="0" cellspacing="0" cellpadding="2" width="100%">';
echo '<tr><td align="center" class="productListing-heading" > '.TEXT_RELATED_PRODUCTS.' </td></tr><tr><td align="center" class="productListing-data">';
echo '<table border="0" cellspacing="0" cellpadding="2" width="100%" align="center"><Tr>';
if (mysql_num_rows($attribute_query)>0) {
while ($attributes_values = tep_db_fetch_array($attribute_query)) {
$products_name_slave = ($attributes_values['products_name']);
$products_id_slave = ($attributes_values['pop_products_id_slave']);
if ($new_price = tep_get_products_special_price($products_id_slave)) {
$products_price_slave = $currencies->display_price($new_price, tep_get_tax_rate($attributes_values['products_tax_class_id']));
} else {
$products_price_slave = $currencies->display_price($attributes_values['products_price'], tep_get_tax_rate($attributes_values['products_tax_class_id']));
}
// show thumb image if Enabled
echo '<td class="productListing-data" align="center">';
if (MODULE_RELATED_PRODUCTS_SHOW_THUMBS!='False') {
echo '<a href="' . tep_href_link(FILENAME_PRODUCT_INFO, 'products_id=' . $products_id_slave) . '">' . tep_image(DIR_WS_IMAGES . $attributes_values['products_image'], $attributes_values['products_name'], SMALL_IMAGE_WIDTH, SMALL_IMAGE_HEIGHT, 'hspace="5" vspace="5"').'</a>';
}
echo '<Br> <a href="' . tep_href_link(FILENAME_PRODUCT_INFO, 'products_id=' . $products_id_slave) . '">'.$products_name_slave.'<Br>@ '.$products_price_slave.'</a>';
}
echo '</td>';
}
echo '</tr></table></td></tr></table></td></tr>';
//DANIEL: end
?>
attachment is just product_info.php file.. install package first