Vertical Slide with Jquery

Hello,

I am currently trying to modify this script: http://www.chazzuka.com/blog/?p=95 .

For now, I have this code:

JS

<script>
$(function(){
	/**
	*	Jquery Horizontal Slide Navigation
	*	webmaster@chazzuka.com
	*	http://www.chazzuka.com
	*	Nov 13th 2008 @ Denpasar, Bali Paradise Island
	**/
	//@ active scroll
    var _active = null;
	//@ max expand in pixel
    var _hmax = 80;
	//@ min height in pixel
    var _hmin = 0;
	//@ loop through matches selector
    $("#recent-in-network ul li").each(function(){
		//@ in/out handler
		$(this).hover(
			//@ hover
			function(){
				//@ child span expand
				$(this).find('.post-ex').animate({height: _hmax+"px"}, {queue:false, duration:300, easing:'easeOutBack'});
				//@ set active to current hovered
				_active = $(this);
			},
			//@ out
			function() {
				//@ slide back
				$(_active).find('.post-ex').animate({height: _hmin+"px"}, {queue:false, duration:300,easing:'easeInBack'});
			}
		);
	});
});
</script>

Code (markup):

CSS

#recent-in-network ul {position:relative;display:inline;float:left;margin:10px 0 30px 0;}  
#recent-in-network ul li {display:inline-block;height:45px;background:#f1f1f1;width:440px;padding:5px;margin:5px 0;-moz-border-radius:6px;-webkit-border-radius:6px;border-radius:6px;}
#recent-in-network ul li .text {display:block;}
#recent-in-network a.title {font:normal 15px/20px segoe ui;padding:5px 3px;text-decoration:none;color:#0080ff;}
#recent-in-network a.title:hover {text-decoration:none;color:#005ebb;}
#recent-in-network .post-ex {display:inline-block; height:0px; overflow:hidden;font-size:11px;margin:10px 5px;}

Code (markup):

HTML

<div id="recent-in-network">

<ul>
<?php if (have_posts()) : while (have_posts()) : the_post(); ?>

<li>

<span class="text">
 
<a class="title" href="<?php the_permalink() ?>" target="_blank">
<?php
$title = the_title('', '', false);
echo truncate($title, 42, '...');
 ?></a> <br />
 
</span>

<br />


<span class="post-ex"><?php echo strip_string(150,get_the_excerpt()); ?></span>

</li>   <?php endwhile; endif; ?>


</ul></div> 

Code (markup):

I try to expand the text in the "post-ex" tag after I hover the "li" but have no luck. What am I doing wrong?