Thanks to Andy Baio, all five parts of The Machine That Changed the World are available online:
The Machine That Changed the World is the longest, most comprehensive documentary about the history of computing ever produced, but since its release in 1992, it’s become virtually extinct. Out of print and never released online, the only remaining copies are VHS tapes floating around school libraries or in the homes of fans who dubbed the original shows when they aired.
Part 1: Great Brains
(post updated to include YouTube embed and link to playlist)