Speaking of fascinating digital portraiture, I don't wanna miss referring you to Andrej Dragan's website. These pictures simply freak me out every time I visit his page. He invented the technique called "retouch of light" he processes his pictures with. As a Photoshop newbie, I simply emailed him and asked for a hint about how this works. He offered me a tutorial for (I think it was) 300 Euros. I don't doubt that it's worth the money, but I know that those images are not only processed in a great way. The actual photographs are of high quality, too. Not speaking of the challenge of directing a person to look a certain way. My conclusion: There are so many things one can experiment with and it's all for free, let's first dedicate our little spare time to that.
Here are the links. Enjoy!