Ok I went ahead and actually looked it up for you.
Here is how it's done.
Multiple Servers on One Machine
Each server process needs to run under a different gamespy account (can be created in the game). Important things to note are:
* The -nohomedir command forces the servers to use the install directory instead of My Documents...
* The -configsubdir=<serverfoldername> will create a folder under ..\UTGame\config\ so each server instance can have it's own ini files
* -login=<login> and -password=<password> as these must be unique
* The servers port is changed with -Port=<port> in the URL, or via the setting in UTEngine.ini
* The servers query port is changed with -QueryPort=<port>
* You must specify -unattended as without it you will get prompted to confirm the upgrade of the server's configuration files. This option needs to be last in the command line.
Note: -configsubdir= does not work unless -nohomedir is specified.