Portuguese Version Here
Oh, many people asked for it, so, I'll do ~ i hope that it'll be good, because I'm not good with explanations.
Which the program that I use?
Gimp 2.8 (you can download it in the site, it's free! http://www.gimp.org/downloads/ )
But you can use Photoshop too, because GIMP looks like with Photoshop, but it's free, more simple and more "light".
I'll explain of a mode that is possible make in Photoshop or GIMP, not much detailed, I wait that you know the basic of the program.
Ah! Have many many patience >//<
The images about what I saying are in the right of the text.
Start with a document of size 100x100 px.
And create a "border" (in other layer) with the size 50x50 so you know that your pixel art is in the size correct.
Now you can make