this is the same princeple for everything ive just done it on a bonnet lol : :
Firstly you have to duplicate the layer:

Then you have to go to Image>Adjuct>Hue/Saturation make sure you tick the colourise button in the corner of the box
pick what colour you want by moving the sliders - just have a play around until you find a good colour or the colour you like

This time ive picked black for the bonnet, if you pick black then you might find it easier to lower the opacity

Once youve lowered the opacity you can start deleting the bits that aren't suposed to be coloured like the lights, trim and other bits and peices

After you've deleted all them bits you can put the opacity back up -- Also now you have to flatten the image or merge layers.

Hope this helped if you needed helping lol

George
Edited by mstwntd611, 26 May 2008 - 05:08 PM.