Any Texture painting tutorials out there?

I need some free texture painting tutorials, preferebly for Gimp ,but I could follow along with a hotoshop tutorial. I am not the best with art so I do not know where to start and I’m trying to give my game a unique feel and not just use free textures. I am planning on creating organic, hard surface, and softer textures. I need some help please! If you know any great ones share with me and anyone else who wants too know.

Almost done: Hand painting tutorial with Gimp or Photoshop, models made with Blender

http://forum.unity3d.com/threads/222854-Hand-Painting-with-Gimp-Photoshop-Low-Poly-Models-Made-in-Blender-Tutorial