Create a bookmark with the following code as the URL

javascript:
timeout=prompt(“Set timeout [s]”);
current=location.href;
if(timeout>0)
setTimeout(‘reload()’,1000*timeout);
else
location.replace(current);
function reload(){
setTimeout(‘reload()’,1000*timeout);
fr4me='<frameset cols=’*’>n<frame src=”+current+”/>’;
fr4me+='</frameset>’;
with(document){write(fr4me);void(close())};
}

Click the bookmark with the tab you want to auto-reload active.
Set the time interval (in seconds) or set it to zero to cancel auto-reload.

http://www.google.com/support/forum/p/Chrome/thread?tid=1a37ccbdde5902fd&hl=en