Changing date format in a drupal template

Hello
I am trying to customize comment.tpl.php (not the core template of course)

I would like the date to render as "time ago" I've seen this as an option in views, but I have no clue how to get the same thing in a template.

here is what I have

<div class="<?php print $classes; ?> clearfix"<?php print $attributes; ?>>
  <?php print $picture ?>
  <div class="content"<?php print $content_attributes; ?>>
    <?php
      // We hide the comments and links now so that we can render them later.
      hide($content['links']);
     print ($id); 
	 print ".&nbsp;&nbsp;";
	 print ($author);
	 print "&nbsp;";
      print strip_tags (render($content));
    ?>
    <br>
    <?php print ($created); ?>
  </div>

</div>

Select allOpen in new window

What do I need to do?