Hopefully it's pretty self-explanatory. Requires a basic knowledge of GIMP tools, but I try to walk you through it so you can pretty much just download GIMP and give it a try (well, understand how to find things, and be familiar with the overall layout of the program!)
The texture I used can be found here:[link]
Honestly, it's really simple. I would LOVE it if you linked back here, but I would love it even more if you guys went out there and made tons of brush sets and texture sets!!
And yeah, I make my textures the same way, but with a 512 x512 image, and saved to the tex folders. But it's the same thing.
Anyway, my eyes hurt so I'm gonna go bury my face in a pillow. Enjoy!