style wp_page_menu

Hey Folks,

after along search a found a code to display only the sub-menu depending on the current page…
This is what did it:
<?php $html = wp_page_menu('title_li=&child_of='.$post->ID. '&echo=0'); echo $html; ?>

But now I don’t have a clue how to style this menu. Can I add something to assign a css id/class?

Here’s the link to the site I’m working on