black and white but with coloured areas

[TwIsTeD_SpArKlE]

i love photos with a selected area or object in colour and the rest in black and white but i cant work out how to do this please help!!

[fotobill]

One way is to desaturate to remove the color then use the history brush to paint the color back into the areas where you want it.

[Hatch]

A good way of going about it in a nondestructive mannor. This gives you the ability to paint back in the color or paint away the color.

Open the image in PS
Add a Hue/Saturation adjustment layer.
Drag the Staturation slider to -100
Since this is a mask now... you can paint back the color areas you would like to keep.

Is this the effect you ar looking for?