erik3d

I've recently tested some free drawing programs,the first one out is alchemy, it's a very basic drawing program but with some cool features like the mirror tool.

The other one is Gimp witch is a fun drawing and editing program, not as powerful as photoshop but has some nice brushes and I deeply recommend it, sadly there seems to not work properly with 64-bit windows and it didn't like my wacom tablet buttons.

There are some tutorials out there for these programs, check out the Blender site !

And finally nDo, haven't tested this yet but it seems like a powerfull little tool, it's called nDo and it's for making normal maps etc.