Seems like it needs to go here on the product_info.tpl.php

Code:
         document.write('<a href="javascript:popupImage(\'<?php echo tep_href_link(FILENAME_POPUP_IMAGE, 'pID=' . $product_info['products_id'] . '&type=' . $lg_image_ext); ?>\',\'<?php echo ((int)$image_size[1] + 30); ?>\',\'<?php echo ((int)$image_size[0] + 5); ?>\');"><?php echo tep_image(DIR_WS_IMAGES . $product_info['products_image'], addslashes($product_info['products_name']), SMALL_IMAGE_WIDTH, SMALL_IMAGE_HEIGHT); ?><br /><span class="smallText"><?php echo TEXT_CLICK_TO_ENLARGE; ?></span></a>');
Just need to know how to replace the "Click here to enlarge" text with my own button.

Thanks for the help,
Sparks