<div id="footer">
    <ul>
        <li><a href="#">Home</a></li>
        <li><a href="#">About</a></li>
        <li><a href="#">Contact</a></li>
    </ul>
</div>

#footer { text-align: center; }
#footer ul { list-style: none; }
#footer ul li { display: inline; }

#footer { width: 100%; overflow: hidden; }
#footer ul { list-style: none; position: relative; float: left; display: block; left: 50%; }
#footer ul li { position: relative; float: left; display: block; right: 50%; }

Home
About
Contact

Home | About | Contact

#wrapper { width:600px; background: yellow; margin: 0 auto; }
#footer ul { text-align: center; list-style-type: none; }

#wrapper { width:600px; background: yellow; margin: 0 auto; }
#footer ul { text-align: center; list-style-type: none; }
#footer li { display: inline; }
#footer a { padding: 2px 12px; background: orange; text-decoration: none; }
#footer a:hover { background: green; color: yellow; }