var banner = new Array();

banner[0]='http://img15.imageshack.us/img15/4504/titulo1.gif';
banner[1]='http://img706.imageshack.us/img706/6720/titulo2.gif';
banner[2]='http://img188.imageshack.us/img188/7061/titulo3.gif';
banner[3]='http://img94.imageshack.us/img94/1198/titulo4.gif';
banner[4]='http://img188.imageshack.us/img188/6931/titulo5.gif';
banner[5]='http://img188.imageshack.us/img188/7632/titulo6.gif';
banner[6]='http://img130.imageshack.us/img130/4483/titulo7.gif';

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)];",60000);