In this tutorial, I show you a pre-created mesh with some sculpting applied, and we quickly go over the seams and UV coordinates. Then we bake out a tangent normal map, and begin painting a texture in Texture Paint mode. After that, we jump into GLSL mode (setting up some extra lights so there’s nice even shading) and paint in a specular map. Finally, we paint on a Bump Map, using the Varonoi Crackle cloud texture for a nice wrinkly/leathery skin texture.
The tutorial has an addendum that fixes the bump mapping problems experienced in this tutorial, view it here: http://www.blendercookie.com/2011/04/14/texture-painting-in-glsl-shading-mode-addendum/