var banner = new Array();
banner[1]='http://i1087.photobucket.com/albums/j464/Hitechbr/logo3yjm2.png?t=1298728285';
banner[2]='http://i1087.photobucket.com/albums/j464/Hitechbr/logo2gf.png?t=1298728231';
document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];