Over the years, PBS has produced a series of programs on the history of empires. In 2003, they made 2 special episodes on Martin Luther. (Liam Neeson provides the narration.) Thanks to Hulu, these are available for your viewing pleasure at any time.
UPDATE: These were available for a very long time but have finally been removed from Hulu’s library. 3/31/14
The PBS website for the the films is still up at this address for the time being. I don’t know about getting the video but there is plenty to read.