Делаем иконкам эффект затухания на JQuery

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript" src="js/script.js"></script>

<div id="wrapper">
		<ul class="social" id="jquery">
			<li class="delicious">
				<a href="#"><strong>Delicious</strong></a>
			</li>
			<li class="digg">
				<a href="#"><strong>Digg</strong></a>
			</li>
			<li class="facebook">
				<a href="#"><strong>Facebook</strong></a>
			</li>
			<li class="flickr">
				<a href="#"><strong>Flickr</strong></a>
			</li>
			<li class="linkedin">
				<a href="#"><strong>LinkedIn</strong></a>
			</li>
			<li class="reddit">
				<a href="#"><strong>Reddit</strong></a>
			</li>
			<li class="rss">
				<a href="#"><strong>RSS</strong></a>
			</li>
			<li class="twitter">
				<a href="#"><strong>Twitter</strong></a>
			</li>
		</ul>
</div>

#wrapper { width:800px; margin:40px auto; }
 
.social { 
list-style:none; 
margin:30px auto; 
width:464px; }
 
.social li { 
display:inline; 
float:left; 
background-repeat:no-repeat; }
 
.social li a { 
display:block; 
width:48px; 
height:48px; 
padding-right:10px; 
position:relative; 
text-decoration:none; }
 
.social li a strong { 
font-weight:normal; 
position:absolute; 
left:20px; 
top:-1px; 
color:#fff; 
padding:3px; 
z-index:9999;
text-shadow:1px 1px 0 rgba(0, 0, 0, 0.75); 
background-color:rgba(0, 0, 0, 0.7);
 -moz-border-radius:3px; 
 -moz-box-shadow: 0 0 5px rgba(0, 0, 0, 0.5); 
 -webkit-border-radius:3px; 
 -webkit-box-shadow: 0 0 5px rgba(0, 0, 0, 0.5); 
 border-radius:3px; 
 box-shadow: 0 0 5px rgba(0, 0, 0, 0.5);
}
 
li.delicious { background-image:url("../images/delicious.png"); }
li.digg { background-image:url("../images/digg.png"); }
li.facebook { background-image:url("../images/facebook.png"); }
li.flickr { background-image:url("../images/flickr.png"); }
li.linkedin { background-image:url("../images/linkedin.png"); }
li.reddit { background-image:url("../images/reddit.png"); }
li.rss { background-image:url("../images/rss.png"); }
li.twitter { background-image:url("../images/twitter.png"); }