In a standard DVD, you will find files with a VOB extension. Open these files with Video Edit Magic. In the Collections window, under the Media Files tab, look up the VOB file's Video Properties for the file's dimension.

If the reported video dimension is 720 x 480 pixels then the video is NTSC. On the other hand, if the video dimension is 720 x 576 pixels then the video is PAL. Standard DVDs also contain a region code that informs the DVD player about the picture standard (NTSC or PAL) used by the DVD. However, for video editing, you can use the dimension to determine the picture standard.

If you have trouble opening the DVD, I suggest ripping the DVD to WMV format for editing. You can use Rip DVD Plus to get a good quality output file.