$(function(){
    $(".switcher")
        .hover(
            function(){
                var id = this.id.split("_");
                $(this).css("background-image","url(./img/header_menu_over.gif)")
            },
            function(){
                $(this).css("background-image","url(./img/header_menu.gif)")
            }
        )
        .click(function () {
            location.href=this.id;
            return true;
        });
});