var banner = new Array();
banner[0]='http://img144.imageshack.us/img144/8259/bannermod.jpg'; 
banner[1]='http://img17.imageshack.us/img17/5769/banner2mod.jpg';
banner[2]='http://img406.imageshack.us/img406/5219/banner3mod.jpg';
banner[3]='http://img696.imageshack.us/img696/1124/bannerbace01.png';
banner[4]='http://img580.imageshack.us/img580/7338/bannerbace.png';

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