A series of Camtasia video tutorials. I did these such a long time ago, back in version 3.5 I think but they're still relevant, particularly for anyone coming to XSI and the rendertree for the first time. I've tried to concentrate on techniques, basic blocks on which you can build rather than trying to be too specific.

The noise tutorials need a couple of custom shader nodes, you can find them here (right click on link, save target as). This pack also includes a sine node, useful for marbles and woods.

Enjoy

• Basic Texturing
  Simple texturing of objects with a brief explanation of how to drive surface characteristics such as transparency or reflections
• Blending and Compositing Textures, use of the mix2colors node
  Techniques for combining textures and shader nodes
• Applying Labels
  applying textures to parts of a surface without using clusters
• More on Labels
  Using boolean nodes to mask mesh areas according to UV value
• Noise Texturing
  The basic principles behind noise and turbulence for texturing
• More Noise
  Using noise and turbulence to modify values
• Distorting images
  Using noise on UV coordinates to distort non-procedural and procedural textures.
• Practical Noise
  Using the methods discussed so far to create useful textures; fire, marbles, stones,
• Bump Mapping
  How bump mapping really works in XSI and how top get it right.
• NPR
  Non Photo Realistic Rendering techniques
• The Toon Shader
• Halftoning methods
  More NPR methods