Leadership deals with the purpose of an organization or individual business and how it will change.
Strategy is about the basic choices of how to achieve the purpose.
There's been a lot of nonsense written about leadership and strategy, which really haven't changed much since Caesar was writing about his Gallic Campaigns. What changes is the environment in which leadership happens. Today's big challenge is how to adapt leadership and strategic principles to work effectively in the Digital Age. I've outlined that in detail in Leadership for a Networked World . Those are two of several articles on Leadership and Strategy that appear on this site.