var banner = new Array();

banner[0]='http://img819.imageshack.us/img819/6487/pxw1.jpg';
banner[1]='http://img819.imageshack.us/img819/6983/pxw2.jpg';
banner[2]='http://img819.imageshack.us/img819/1809/pxw4.jpg';
banner[3]='http://img819.imageshack.us/img819/9914/pxw3.jpg';


document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];

setInterval("document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];",3000);