The css part of it is easy you would just need to create a background image with the hover effect you want,
Code:
#nav a:hover{
background-image:url(hover.jpg);
}
This way it wouldn’t be as smooth as it is on that flash site, but there is a way to do it in jquery. as I recall it is very easy to do. just search fade in.
I got this off of the jquery website. its not what you need because this shows hidden divs, but it would look similar.
Code:
$(document.body).click(function () {
$(“div:hidden:first”).fadeIn(“slow”);
});