You can try the patch method. Rip the dvd to the hard drive and use these instructions for IFOEdit: http://forum.lgsoftwareinnovations.com/showthread.php?t=25689 Not guaranteed to work.
Or you can reencode. Get FAVC http://favcfavc.googlepages.com/ Make sure to get the necessary programs for it from that page. Rip the dvd to the hard drive, import to FAVC and set the output as NTSC within FAVC.
Many DVD players can play both. Just ensure your DVD has the region coding removed.