Colouring Help

Hi, I was wondering if anyone had a tutorial or knew how to achieve colouring like these and how to get the textures to pop out like they do in the icons.
I'm using Photoshop CS3

I'll give a few examples:



Also a bigger image colouring after the cut


the icons are by hurtillusions  
I did ask the creator if they had a tutorial or how they made them.. but they said they just found it by fiddling around :(

These are some of the nicest icons I've ever seen and I'd love to do something like that.
Thanks for the help,