Small office setting up Exchange 2003 to use OWA

[spyd3r]

We have a small office with a windows 2003 server which is running Mac software as well as serving as a file server and backup manager. I need to use this same server as an exchange server for the OWA properties although our parent organization handles all email routing.

Is it possible to install and maintain Exchange Server 2003 on a single Windows 2003 Server without designating it as Network Load Bearing and/or clustering?

If so, can someone give me directions and/or settings to create this stand alone server?

Thanks!
Spyd3r