How can I give id values to my navbar links?

Hello,

I’m trying to create a graphical navbar on my site, similar to those at blazersix.com and ndesign-studio.com. At those sites, the li elements have classes like “#nav-about” and “#nav-home.” On standard WordPress sites, these classes do not show up.

For instance, here’s what the code for a navigation link looks like on ndesign-studio:

<li id="nav-home"><a href="http://www.ndesign-studio.com/">Blog</a></li>

…and here’s what the code for a nav link looks like on my page:

<li class="page_item page-item-3 current_page_item "><a href="http://www.lightningux.com" title="Home">Home</a></li>

So on my page, there is no ID that clearly identifies each navigation item. Does anyone know how I can make my WP installation output links like the former one, where each navigation link has an ID that can easily be referenced from CSS? Thanks.