There are times, when as a network administrator, you have a need to remotely reboot either a server or a workstation.

This can be achieved from a cmd prompt, using the shutdown command.

shutdown /i

From a 2003 Server will give you a dialog box where you can add computers, give the users a warning of what you are up to. You would not be able to script this.

There is also  

shutdown /r /m \\computername /t seconds /f {force shutdown, no warning}

In an ideal world, a remote control tool, such as Microsoft Remote Desktop or VNC could be used, and that way you can logoff, ensuring that all applications are closed, and also log back on after the restart.