Depends on how much time you have and what according to you ultimately is leadership.
You can be the judge of that above.
For PPT's you have options of Slideshare and Authorstream. They have endless material.
Incase you are running short on time then just go to that above link and download whatever you find
there as the material there is refined and can be treated similar to an enriching self study course.
Here's a link for All Leadership PPT Slides
Start with Introduction to Leadership Theory and end with Effective Leadership.
Contact the blog owners if you have any doubts w.r.t the material there. They are genuinely helpful.
As for the whitepapers you can search citehr or google them.
I don't think there are many as such to begin with and if there are
they would require a solid background into behavioral science.
You can dwell into them if you have the time and behavioral acumen for such things.
If you want my take, I'd say Leadership must always be studied and defined in its context.
In my opinion Leadership is wrongly used as noun, as a label for all things where in reality
it is actually a process that can be viewed within a context.
You can use this frame of reference to build your material.
Context includes Individual Ability, Followers, Environment and Opportunity.
Outside the context, for an individual, Leadership is a behavioral choice.
When one makes up their mind about it you can help them to achieve their
Leadership goals with those above variables in mind.
If you find it worth your recipe, you can use my above opinion as an conclusion to seminar presentation.
Erstine 21st November 2013 From India, Aurangabad