$(document).ready(
    function(){
        var so = new SWFObject("snowball.swf", "overlay-popup", "800", "600", "8", "#336699");
        so.addParam("quality", "medium");
        so.addParam("wmode", "transparent");
        so.addParam("salign", "t");
        so.write("overlay-popup");
        showOverlay($("#cont"));
    }
);

function showOverlay(elem){
    elem.overlay({
	top: 50,
        mask: {
            color: '#000',
            opacity: 0.5,
            maskId: 'exposeMask'
	},
        closeOnClick: false,
        load: true
    });
}