When it comes to YUV as opposed to the colour friendly RGB, usually looking at the connections the YUV will be in that left to right order. However, your questions implies you have coloured cables from your component. Have a look at the back of the DVD (?) where you connected the coloured cables and you should see YUV labels to tell you which is which and from there you will be able to work out the colours.
thanks malice. the leads are coming from my screen which dont realy help all they say is: PR/CR/R - PB/CB/b - YG on the back.i take it this means red,blue,green??
Does this mean Y=Red U=Blue V=Green on the component box?
A converter as described means to me that you have a component source (eg DVD) and you want to play it through a screen which doesn't have component, only RGB or VGA. If your screen has the ability to accept a component signal on its PR/CR/R - PB/CB/b - YG connections (which it has by this nonclementure), then there is no ned for a converter. Just stick your component outputting unit directly to the component inputs with a straight lead. You may need to configure your screen to tell it to expect a component signal, but that should be it really.
FWIW have a read of this article about YUV, Y-Pb-Pr, it also has the colours you mention! Y = Green, Pb = Blue Pr = Red, and Y-U-V is "interchangeable" with Y-Pb-Pr.