I am currently moving my SVN server from my home server to my remote server so I can access it more easily from other locations. My remote server is not backed up so I want
EFraim mentioned rsync while I wrote this so that's covered.
If you don't want to work with that, the Subversion Book offers the svnadmin dump --incremental option explained here:
svnadmin dump --incremental However, to do this successfully, you have to juggle with revision numbers - rsync'ing the raw repository data directories will be easier.
The hard part will probably be setting up rsync so your local and remote machine can communicate securely (i.e. set up an SSH service on the 2003 server). DeltaCopy that Wim mentions is very interesting and would be my first shot; for command line operation only, here is a howto on how to get Rsync running as a service on Windows 2003.