"Good knowledge of Photoshop is a must"? Uhm... I'm sorry, but that is extremely far from the truth. As a matter of fact, you're supposed to work on sprites through Paint essentially since it's adapted for just that. And I in my case can then later add it in to Flash to either animate it or work on comics or it. I'm just saying, Photoshop isn't a must - and good knowledge of it is neither so.
Still, I really do appreciate this tutorial.
It helps me a lot, and I hope it'll help me come closer to be capable of doing good sprites.