Magento :
Using app/design/frontend/default/theme/template/catalog/product/view.phtml

how to display my text message on my selected products,

workout :

<?php
            $productId = '42150';
            $product = Mage::getModel('catalog/product')->load($productId);
            if( $productId == '42150' )
            {
                echo "Test";
            }
            ?>

if i wrong pls correct me.