The solution, if your list items can be display: inline
is quite easy:
#footer { text-align: center; }
#footer ul { list-style: none; }
#footer ul li { display: inline; }
However, many times you must use display:block
on your <li>
s. The following CSS will work, in this case:
#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%; }