Color Encoding
Color correction of a video picture is not automatic in the NTSC standard. Receivers are instead built with tint adjustment controls that the viewer can manually operate. This can cause the graphics on your Wii games to be oddly colored if not adjusted properly.
Frames Per Second
NTSC televisions use 29.97 frames per second as opposed to the PAL format, which uses 25 per second. This causes the animation in a game played on an NTSC Wii to appear smoother.
Resolution
NTSC uses 525 lines of resolution on screen, versus PAL's 625 lines. This will cause the graphics on games played on NTSC Wii consoles to be slightly less detailed.
Where NTSC Is Found
NTSC is mainly used in North America, South America and scattered parts of Asia.