Free online resources
Strategyzer.com contains a number of free resources, including templates for the tools they have developed, the Business Model Canvas and the Value Proposition Canvas, and videos. Alex Osterwalder, Strategyzer co-founder, has written a number of books that outline the core concepts of the Strategyzer toolbox.
Steve Blank shares an enormous amount of his resources on his website, including slide decks and videos about lean startup concepts. Steve's area of expertise is Customer Discovery and he encourages startups to "get out of the building" to gather customer data.