As I live in PAL land I prefer most things to be in PAL format because I can't stand the 3:2 pulldown used on NTSC films, however since I got a projector (well, built one, see LumenLab.com) I now have a truly progressive display which means no 3:2 pulldown on NTSC DVDs (unless they're burnt-in) and WinDVD has an option called "PAL Truspeed" that plays PAL films at true film framerate, slowing the video & audio playback so the pitch is correct. I don't know how/if it copes with sending the slowed digital stream to an external amp, will have to try that if I can find my motherboard manual for the SP/DIF output socket.

When I first got my definitive LDs I was playing around with converting them to PAL format and instead of speeding up the audio to compensate for the 4.096% speedup I tried timestretching with pitch preservation, it works but I couldn't find a program that would do it with any real competance, while the speech was fine some tones in the music sounded 'glitchy' due to the sample overlapping method timestretching uses to preserve the pitch.