This website is a really good, free place to learn many photoshop techniques or even 3D techniques if you can find it, it's psd.tutsplus.com.

I have just been watching an amazing video tutorial on how to create hair in photoshop and make it look almost photo realistic with nothing more than a custom brush and CS5 (or higher). The video can be found at this link here :

http://psd.tutsplus.com/tutorials/painting/paint-realistic-hair/

Sadly I can't upload the video to my blog for easier viewing, but definitely worth a watch and I think it has helped me a lot, some of what he shows you seems really obvious but I have never seen a tutorial use the same techniques that this guy shows.