FYI NTSC changed it to 15.73426kHz for color, not sure why Wikipedia rounded up the color burst 3.58MHz from 3.574595MHz its only significant because it was formulated so the harmonics didn't screw with anything else and they could add color with getting rid of all the black and white tvs.

I think MC chris has it right http://mcchris.com/ http://en.wikipedia.org/wiki/Mc_chris