If you have ever played around with doing unattended installs of Exchange, you will know that there is limited support for this. For one thing, it is not supported to perform an unattended install of the First server in an organization (though I've seen it work before...). Furthermore, you should only perform unattended installs in a Native organization. Performing unattended installs to a Mixed mode organization is not supported.
Now that we've gotten that out of the way, there may be a few courageous souls that would also like to REMOTELY install Exchange. Yep - I mean run a script or command from one computer to install Exchange on a separate computer. While theoretically this will work, the supportability of this is probably even more limited. If you do try and get this to work, you must set your script (or command) to run interactively with the desktop of the remote server. Yep - that's right, folks, non-interactive setup of Exchange is not supported for Exchange 2003 (or 2000). The good news is that with Exchange 2007, this all changes, as you can simply execute a Powershell script. I haven't tested unattended installs of Exchange 2007 yet, but I would imagine that the interactive barrier has been lifted. BTW - you can now script the first server install with Exchange 2007 as well. Cool, huh.
One example of a tool that allows you to remotely run a command is PsExec. PsExec was developed by SysInternals, which is now part of Microsoft. It is included in the PsTools bundle (or available separately), and it allows you to run commands against remote computers. In the example of an unattended setup of Exchange, the command would look something like this:
psexec \\computer -i -u "DOMAIN\user" -p password -e "D:\setup\i386\setup.exe" /UnattendFile "C:\exchange_unattend.ini"
The parameter -i tells it to run in interactive mode (interact with the desktop), the -u command specifies the username to run the command as, the -p is the password, and the -e tells it to load the user's profile.
Running this command will display the splash screen on the remote computer, and it will proceed through the Exchange setup, then the splash screen will exit automatically at the end of setup, and you'll have a new Exchange server.