CAREER PLANNING RESOURCES
Mindtools is a great place to start when you're considering the next stage of your career, with loads of free resources and clear explanations of different tools and systems.
Likewise, Businessballs (no idea where they got the name, but brilliant content nevertheless!).
Take a look at my Quora profile to see loads of career FAQs. These also demonstrate my general approach to career change.
Finally, some typically awesome career advice from George Monbiot.