Hi Richard,
The effect is created by duplicating the image to make two copies, then desaturating the copy and laying it over the top of the colour version. Then add a layer mask and with a soft round brush paint back in the areas of colour that you want to show through. It really is that simple. I normally do a curves adjustment layer on the desaturated copy to make the blacks really black and boost the oveall contrast.
Thanks for stopping by and for your kind comments.