You can get PAL-NTSC (or NTSC-PAL) converters but the quality can be crappy especially if you get a cheap converter.
If you can spend a grand (USD) you can get an external de-interlacer scaler that accepts either NTSC or PAL and delivers a constant progressive scan output in a variety of scan rates including 540p (goes right into an HDTV component video 1080i input)and 720p. The Lumagen and DVDO units also do an excellent job of making the progressive scan, too, and require neither manual selection of NTSC/PAL nor manual selection of film/Live-video.
Video hints:
http://members.aol.com/ajaynejr/video.htm
(With some of the upscale converters too, the bottom of the PAL picture could be cropped slightly since PAL is 576p after de-interlacing while 1080i conversion may take only 540 scan lines from each frame.)