If your lucky enough to have a TV that supports the RGB connectors, just go buy a RGB XBox cable and use it.
With the PS2 I know theres away to force it to play PAL or NTSC but I don't think there is a way to that with the XBox (yet).
Now from what I've been told the newer PAL TVs, mainly the ones in the UK don't mind playing NTSC movies or games. But the US NTSC TVs don't take it so well. I know they make hardware that site in between your hardware (being your XBox) and your TV and will convert the signal. I will see if I can find the page that sells it again.