We got fed up with this real quick where I work, so I wrote a little app called DVD Region Code Unlock that you can run to allow (on the first time the user tries to play a DVD) to set the region code. Using this simple app on the systems allows the user to set the region code once. (After the initial time, an admin password will be required to re-set the region code.)
[robg adds: I haven't tested this app.]

