For anyone who wants to get some more experience on how to create shaders and textures in Cycles for Blender, this book is a good choice. The book has a number of great examples for creating various materials in different ways. It also gets you used to working with the node editor, the render settings for cycles, making your materials more efficient and how to create texture libraries for later use.
If your a cg artist looking for practical examples I would recommend this book to you. Im only three chapters in and I feel more comfortable working in cycles already. The book is not perfect and it does not explain all of the technical details, however its a great way to get your feet wet, and get more familiar with the work flow for Cycles. Check it out at Packt Publishing: http://www.packtpub.com/blender-2-6-cycles-materials-and-textures-cookbook/book
Below are a few examples of my progress so far.