http://academicearth.org/lectures/redistributive-and-progressive-taxation
This lecture from Harvard's Justice class is about 1 hour. It's about Libertarianism, with emphasis on individual rights and the tax code. This subject came up recently in the "Family of 3 Lives on $20,000 per year" thread.
Aside: I love this site... they have great free lectures from Harvard, Stanford, famous businessmen, etc.