Yes,
I've gone from PAL to NTSC many times, results are excellent. haven't tried the other way around. It maybe a little tricker and it may help if you know what the original source was to get the best results. If it was film then you can do the inverse telecine trick and produce a 24p DVD which BTW should play OK in both PAL and NSTC.
If the soure material was video should be just fine, probably work better than going PAL to NTSC as VV only has to remove frames not 'make them up' although it seems to do an excellent job at that.
Thanks farss. The source is video shot by my camera in MPEG-2 format widescreen.
I already have all the editing done and an NTSC MPEG-2 rendered, I guess I will have to re-render in PAL widescreen. Since I will be doing this "blindly" (no way to check the results) is there anything that I have to keep in mind?