aiuto con jquery e menu a 3 livelli

[Vindav]

$(document).ready(function () {   
	$('#nav li').hover(
		function () {
			//show its submenu
			$('ul:first', this).slideDown(100);
		}, 
		function () {
			//hide its submenu
			$('ul', this).slideUp(100);         
		}
	);
});