var banner = new Array();

banner[0]='http://img219.imageshack.us/img219/6139/motorsportracingteamfi2.jpg';
banner[1]='http://img687.imageshack.us/img687/8282/logomrtcarbono2o.jpg';
banner[2]='http://i31.servimg.com/u/f31/13/41/43/38/portad10.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);