I’m doing the opposite at the moment – creating the NTSC version of a PAL DVD project. In my case I was able to go back the the original After Effects project and create an NTSC composition into which I dropped the existing PAL comps. I rendered this out as uncompressed and then used Compressor to crunch the MPEG2 video file.
In DVDSP, I saved a copy of my PAL project and deleted all the video files from the assets bin so that I could change the project settings to NTSC. All the tracks (including chapter markers), menus, scripts etc remained in place so I then imported the new NTSC assets and dropped them into place. The chapter markers sometimes need tweaking so that they sit on the start of a GOP in the new video file, and it looks like I’ll have to check the subtitle files carefully for timecode hiccups, but other than that, it went very smoothly.
Matthew