CGBootcamp’s Leo Covarrubias with part 3 of the series on Maya CGFX Shader Writing which covers adding a Blinn specular highlight to the shader and breaking the code down into seperate functions for lambert and blinn components. If you have missed the first two of the series, check them out here.
Maya: CGFX Shader Writing 03: Blinn Specular Highlight from CG Bootcamp on Vimeo.