Think of applying this idea.
$time = mktime()+3600;
$date = date("l, d-M-Y H:i:s", ($time));
expires=$date GMT;
I use the above to set a cookie that'll expire in one hour.
mktime() is the current time in seconds.
I add 3600 seconds to that to get $time.
The $time is then formatted the proper way for setting cookies.
This works great for me. I hope it does for you also.
NOTE: Some operating systems will not set your cookie, unless you set the expiration to about 9 hrs. I know Windows does that.
Richard.
geocities.com/akindele/