I didnt think it was possible to use NTSC appliances with PAL!
It's a little more complex than that. Every color TV system in the world starts with a picture made up from the three primary colors: red, green, and blue. The main differences are then the scanning rate (i.e. the number of lines per frame & the number of frames per second) and the method by which the color signals are encoded for broadcast.
If you connect by composite video or S-video leads, you are connecting a signal which is already fully encoded to NTSC or PAL standards, so it won't work unless the TV is designed to handle the appropriate system.
However, if you connect the color signals directly, either via direct RGB inputs or by Y/Pr/Pb (Y/Cr/Cb) component inputs, then you bypass the color encoding entirely and there is only the matter of the different scanning rates to be considered.
The scanning rates of the U.S. and U.K. systems are close enough that many modern TV sets will actually synchronize properly even if not designed specifically for the "other" system (horizontal rate: 15,734 Hz vs. 15,625 Hz; vertical 60 Hz vs. 50 Hz).
So it can't be guaranteed to work for every TV, but in many cases a British set will actually correctly display an American video signal if it is connected on the RGB or Y/Pr/Pb component inputs.
If you want the more complex technical explanation, I posted a much longer discourse on this subject in the
Technical Issues thread. Scroll down to reply #34, 5/27/06.