A few people have asked for a guide on the technique I used for my Guyver painting, so here you go!
It's just a basic description of my process so is far from an exhaustive tutorial, but feel free to ask any questions if you'd like me to elaborate on any of the points.
I used Corel Painter 10 for my painting and Photoshop CS3 for the final adjustments, but I'm sure the whole thing could be produced in photoshop if that's all you have to hand.
I can't take full credit as I actually picked up the foundations of this technique from a blog post by the extremely talented Sam Nielson. Please check out his blog, you won't be dissappointed.
Part 1 of that post can be found on the The Art Center Blog here and part 2 here.
I highly recommend reading them as Sam explains the process far better than me!