Poweroff is a small program for Win95/98/NT/W2K/XP to schedule a shutdown/reboot/logoff/poweroff/Standby/Hibernate/Lock/Wake-On-LAN at a certain time. I also support command line options that allows poweroff to be used in batch scripts. It has a built-in scheduler, it allows you to run a program before doing the action, you can give a warning message to the user, wait for a process to finish before doing the action and full remote control is supported.
http://users.pandora.be/jbosman/applications.html