This article with sample source code describes what BRDF (Bi-directional Reflectance Distribution Function) lighting is and how to do it in realtime using textures. BRDF is basically a weight function with which the light on a surface is modulated to determine what color the eye sees.
Dot Product Texture Blending and Per-Pixel Lighting
Fake Phong Shading
May 2002 - Daniel Vlasic
This thesis describes techniques available for aproximating phong shading in real time. The best technique described is the Blinn shading technique, that maps the vertices onto a specularity map.
Advanced Shader Programming: Diffuse & Specular Lighting
July 2002 - Wolfgang Engel
This article shows how to do diffuse and specular lighting with pixelshaders 1.1, 1.2, and 1.4 for DirectX.
Advanced lighting and shading with Direct3D 9
Feb 2003 - Michal Valient
This article explains lighting models that goes beyond normal diffuse and phong shading, e.g. Fresnel Term (reflexion), Oren-Nayar (diffuse), and Cook-Torrance (specular). It also shows how to implement them using shaders in Direct3D 9.
June, 2002 - Matthias Wloka
This article shows how to implement fresnel reflection with DirectX 8.1, using either vertex shaders or pixel shaders.