For those who want to go beyond the resources mentioned, I also recommend the following:
GameStorming: A Playbook for Innovators, Rulebreakers, and Changemakers by Gray, Brown,and Macanufo -- An excellent receipe book for helping groups of people explore ideas, problems, and solutions.
This is Service Design Thinking by Stickdorn and Schneider -- This textbook explains design thinking in the context of creating/innovating services, describes practical techniques, and includes case studies. It's also beautifully designed.
Chapter 7: "Getting Personal: Developing Yourself as a Design Thinker" in The Design of Business by Roger Martin -- Many kernals of useful wisdom here, though a bit more "thinky" than practical.