Check out this code snippet on JSFiddle: http://jsfiddle.net/PZgn8/8/. It's interesting to see how the rendering differs between Chrome 27 and Firefox 21. Despite the difference, I believe Firefox is actually displaying the desired outcome.
<ul style="text-align: center;">
<li>
<a href="#">One</a>
</li>
<li>
<a href="#">Two</a>
<ul>
<li>
<a href="#">Two's child</a>
</li>
</ul>
</li>
</ul>
I require the list items within the nested ul to be centered as well, not aligned to the side.