Comment centrer un menu d'un site html ?

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!--
Design by Free CSS Templates
http://www.freecsstemplates.org
Released for free under a Creative Commons Attribution 2.5 License

Name       : Vestibule 
Description: A two-column, fixed-width design with dark color scheme.
Version    : 1.0
Released   : 20130406

-->
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<link href="/menu_assets/styles.css" rel="stylesheet" type="text/css"><meta name="keywords" content="" />
<meta name="description" content="" />
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>Musique De Ouf !</title>
<link href="http://fonts.googleapis.com/css?family=Oxygen:400,700,300" rel="stylesheet" type="text/css" />
<link href="style.css" rel="stylesheet" type="text/css" media="screen" />
</head>
<body>
<div id="wrapper">
	<div id="wrapper">
		<div id="menu" class="container">
			<div id='cssmenu'>
<ul class="blue">
	<li><a href="#" title="home" class="current"><span>home</span></a></li>
    <li><a href="#" title="products"><span>products</span></a></li>
    <li><a href="#" title="blog"><span>blog</span></a></li>
    <li><a href="#" title="contact"><span>contact</span></a></li>
</ul>
</div>
		</div>
	</div>

/* Menu */

#menu { 
text-align:center; 
} 

body {
	padding: 50px;
	margin: 0;
}

ul {
	padding: 5px;
	margin: 10px 0;
	list-style: none;
	background-color: #;
	border-bottom: 1px solid #e7e7e7;
	float: left;
	clear: left;
}

ul li {
	float: left;
	display: inline; /*For ignore double margin in IE6*/
	margin: 0 10px;
}

ul li a {
	text-decoration: none;
	float:left;
	color: #999;
	cursor: pointer;
	font: 900 14px/22px "Arial", Helvetica, sans-serif;
}

ul li a span {
	margin: 0 10px 0 -10px;
	padding: 1px 8px 5px 18px;
	position: relative; /*To fix IE6 problem (not displaying)*/
	float:left;
}

/*BLUE*/
ul.blue li a.current, ul.blue li a:hover {
	background: url(images/blue.png) no-repeat top right;
 	color: #0d5f83;
}

ul.blue li a.current span, ul.blue li a:hover span {
	background: url(images/blue.png) no-repeat top left;
}

#cssmenu { display: inline-block; }