HD is not PAl neither NTSC, but has NTSC-land time bases (23,98fps, 29,97fps, 59,94fps) and PAL-land time-bases (25fps, 50fps).
PAL-land DVD players are able to play NTSC DVDs but NTSC-land DVD players are not able to play PAL DVDs.
No idea if PAL BLU-RAY players are able to read NTSC-land BR discs. I guess yes, but before mastering your movie at 23,98fps you should have clear if this is possible.
rafael
http://www.nagavideo.com