<style><!--
body {width: 800px; margin-left: auto; margin-right: auto; text-align: center}
#main {width: 800px; text-align: left;}
--></style>
</head>
<body>
<div id="main">
Here goes all your stuff.
</div>
</body>
the margin-left and right auto are for firefox and the text-aligns are for internet explorer.