Much more in depth
Put those terms in an internet search engine to get the links:
This will carry you beyond the core level, for those who wish to go further.
Creativity Links by C. Osborne - This page links to great resources on creative thinking.
Edward de Bono's Methods & Concepts of Lateral Thinking - This page provides an overview of deBono's ideas about creativity.
Introduction to Creative Thinking by R. Harris from VirtualSalt - This page compares critical and creative thinking and discusses the myths of creative thinking.
Tutorial on Creativity, Brainstorming and Innovation from Infinite Innovations Ltd. - This tutorial provides basic information about creativity, brainstorming, and innovation. It also provides ideas and activities.
Creativity Pool - This is a database of creative and original ideas. Submit your own or check to see if someone else has thought of the same thing.