Getting child LIs in a UL

Getting child LIs in a UL

Sorry for the noob question.

I have an UL like this:

<ul class="menu">
<li class="selected">Overview</li>
<li>Menu Item</li>
<li>Menu Item</li>
<li>Menu Item</li>
</ul>

If I want to set the CSS Class for the first LI, why does this not work:

$('.menu li:eq(0)').addClass("active");

should it be

$('.menu').('li:eq(0)').addClass("active");

or

$('.menu')find('li:eq(0)').each().addClass("active");

i dunno....