Layer Settings, Gradient Maps and some colouring. (PS7)
This is a basic colouring effect tutorial. It's not an earth shattering technique, and has undoubtedly been done before, but it's effective and people should really learn to work with the original picture before covering it up with brushes.
So we're starting with this;
and we're going to end up with this:
Follow the link back to my icon journal for the image heavy tutorial.