<?php echo urlencode('http://'.$_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"]); ?>
и поставяш този код:<div class='post-body entry-content'>
<dataost.body/>
<iframe allowTransparency='true' expr:src='"http://www.facebook.com/plugins/like.php?href=" + dataost.url + "&layout=standard&show_faces=false&width=100&action=like&font=arial&colorscheme=light"' frameborder='0' scrolling='no' style='border:none; overflow:hidden; width:450px; height:40px;'/>