$(function() {
        // set opacity to nill on page load
        $("ul#menu span").css("opacity","0");
        // on mouse over
        $("ul#menu span").hover(function () {
                // animate opacity to full
                $(this).stop().animate({
                        opacity: 1
                }, 'normal');
        },
        // on mouse out
        function () {
                // animate opacity to nill
                $(this).stop().animate({
                        opacity: 0
                }, 'normal');
        });
});