Most people will not be able to easily tell the difference between NTSC and PAL. The main difference starts with the electrical power system that runs behind the color transmissions. In the United States, electrical power is generated at 60 hertz. The signal behind the NTSC broadcast format is set to send out 60 fields per second. Most televisions use a interlaced system, so the NTSC signal sends out 30 lines of the image, followed by another 30 alternating lines. Basically, that results in 30 frames of a complete image appearing every single second.
In Europe and other countries, electrical power is generated at 50 hertz. Televisions that utilize PAL as the broadcast format only produce 25 frames of a complete image appearing every single second. This causes problems with the proper display of motion, as it makes actors move a bit faster because of the difference in frames per second that are showing movement. If you are trying to watch a PAL movie on a NTSC television, you need to add 5 frames per second, or the motion of the film will be very jerky or slow.
General rule of thumb, use NTSC if you are in the states, and PAL if you are in Europe.
