I believe it’s been online free for quite some time! By all means check a young Thomas Sowell in some of the discussion session following the documentary part; his first appearance is in episode 4 or 5.
Yes, it was... then the videos stopped working, now it seems that they have updated it with a "captcha" to stop folks from 'hot-linking' or otherwise embedding the videos into blogs.
I just rediscovered that the videos work again - after downloading the entire collection for my video library. :)