$(document).ready(function() {
    if(isThisBrowserIE6() != true) {
        $('li.wp_item').hover(
            function(){$(this).find('div.wp_item_tooltip:hidden').fadeIn(250);},
            function(){$(this).find('div.wp_item_tooltip:visible').fadeOut(250);}
        );
    };
});

function isThisBrowserIE6() {
    return ((window.XMLHttpRequest == undefined) && (ActiveXObject != undefined))
}