Despite industry efforts to enforce DVD region limits, there are a lot of legitimate times for using DVDs coded for other regions in the in the US. A great example of this is in schools. Most international DVDs that are perfect for History courses and specifically for World Language courses where teachers want students to see and hear the language with native speakers in local context. Since the typical built-in applications with Windows or OS X have artificial limits to the number of times you can change regions, something is needed to bridge the gap.
Enter VLC. This is a wonderful piece of free and open source software for multimedia playback. They are even branching out into media conversion. It is a very mature tool and highly recommended. Using it instead of the Apple DVD Player.app or the built-in Windows apps you may be using is a great solution.
Other workarounds might include resetting the region change counts, etc. with the programs but that is a waste of time IMHO. Once you download and do the drag and drop install (on Mac OS X) you will be able to go into your CD/DVD System Preferences and change the mapping of what to do when you insert a DVD from the Apple DVD Player to VLC.
After you have mapped it there in your System Preferences (in OS X) when you insert a DVD of whatever region, VLC will launch and give you an initial controller palette. Pressing play will then prompt for the user to tell it where to obtain the media and in general all you will need to do is click over to the ‘Disk’ tab as it will recognize the DVD and click play. You also have full-screen viewing options as well. Playing the DVD through VLC will not prompt for a region code change.
VLC is not only great for handling region code issues with DVDs, but great as an all-around media player for Quicktime movies, .avi and other formats.