// requires prototype 1.6 or higher
function fixPNG() {
    if (Prototype.Browser.IE === true) {
        var version = parseFloat(navigator.appVersion.split('MSIE')[1]);
        if ((version >= 5.5) && (version <= 7) && (document.body.filters)) {
            $$('.ie-fix-opacity').each(function(el) {
                console.log('fixing opacity');
		        var cBGImg = el.currentStyle.backgroundImage;
		        var cImage = cBGImg.substring(cBGImg.indexOf('"') + 1, cBGImg.lastIndexOf('"'));
		        el.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + cImage + "', sizingMethod='scale')";
		        el.style.backgroundImage = "none";
            });
        }
    } 
}
document.observe("dom:loaded", function () {fixPNG();});