Скрипт такой:
<script type="text/javascript">
	 
		$(
			function() {		
				   
				$("#menu-level-1> a.item, a.item-selected").hover(
				   function(){
				   var elm = "#light #menu-level-2-"+$(this).attr("id");
				   $(elm).css("top",$("#menu-container > #dark ").offset().top + $("#menu-container > #dark").height()-2);
				   $(elm).css("left",$(this).offset().left);
				   
				   				   
				   if(this.className ="item")
				      this.className = this.className.replace("item","item-selected");		
				      
				   $(elm).css("display","inline");
				   //$(elm).css("visibility","visible");					
				   							   
				   },
				   				   			   
				   
					function(){
						var elm = "#light #menu-level-2-"+$(this).attr("id");
						$(elm).css("display","inline");	
						
					}
				);
</script>