Pen and ink lessons

Here's about shading technique.

I learned about these shading techniques from a bunch of sites, but these were the most helpful:

• Pen and Ink Lessons - Line and Value - Explanations and examples of several shading techniques.
• Basic Pen Strokes for Ink Drawing - A quick overview of several shading techniques.
• Cross-hatching - Examples of cross-hatching.
• Stipple Portraits - Examples of stippling.
• Basic Contour Hatching - An introduction to using curved hatching lines to create the illusion of depth. (Free registration required to see this lesson.)
• How to Shade a Pencil Line Art Cylinder - A short video from ExpertVillage.