var banner = new Array();

banner[0]='http://img816.imageshack.us/imG816/2747/38759525.png';
banner[1]='http://img207.imageshack.us/img207/1434/logogamezzone.png';
banner[2]='http://img412.imageshack.us/img412/5053/designzone.png';
banner[3]='http://img243.imageshack.us/img243/4923/informatica.png';
banner[4]='http://img213.imageshack.us/img213/1350/jornalismoeentreterimen.png';

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)];",10000);