I've used this in the past to style the current page in the menu:
.sf-menu .current_page_item a,
.sf-menu .current_page_ancestor a,
.sf-menu .current_page_parent a,
.sf-menu .current-menu-item page_item
{
border-bottom-color:#fff;
color: #fea904;
}
but for this (beta) site it doesn't seem to be working http://mamoo-kids.dreamhosters.com/beta/about/. I can see it flash on the color specified, but then it goes back to the default. Does typekit effect that I wonder?