Good luck on something that 'Just Works' (tm)! I have searched for this myself with no real good results. I have NOT tried anything I'm about to say, because 1) I am lazy and 2) I have a NetFlix account, I just queued the ISO's that I had that were PAL.
[Assumed as correct by reading it at a few different places]
The best you will get is a movie without chapters or menus. You can mount the ISO with Daemon tools or Nero's ImageDrive (or whatever it's called) and rerip it with NeroVision express. Supposedly during the ripping process, it will convert it to whatever setting you give it. PAL->NTSC, NTSC->PAL. Then burn the newly ripped ISO.
[/Assuming]
If you attempt this and it works, please let us know how it turns out
.