WpRecipes.com - Daily recipes to cook with WordPress

The first thing to do is to create the function. To do so, paste the following into your functions.php file:

function time_ago( $type = 'post' ) {
	$d = 'comment' == $type ? 'get_comment_time' : 'get_post_time';
	return human_time_diff($d('U'), current_time('timestamp')) . " " . __('ago');
}

Once done, you can use the function in your theme files:

<?php echo time_ago(); ?>

Thanks to UpThemes for this trick!