[Stasik]

погляди
http://de3.php.net/manual/en/function.mktime.php
http://de3.php.net/manual/en/function.time.php
http://de3.php.net/manual/en/function.вфеу.php

$time=time();
$time=$time-60*60*60*24;
$nowDate=date("m.d.Y H:i:s",$time);

день назад.....