Doug Knox's User Display Settings page contains:
This small utility will allow all users on your system to have their own screen resolution, and have this setting retained at each logon. This application is freeware.
For users upgrading to v2.0, I recommend running the utility, for the first time, from the Run dialog with the /R command line switch. Example:
C:\Program Files\Doug's XP Stuff\XP_UserDisplay.exe /R