A series of history lectures on the Eastern Roman Empire (aka Byzantine Empire) entitled, "12 Byzantine Rulers" is available online. Since the story of the Byzantine Empire is an essential part of the story of the Orthodox Church, it's worth listening to.You can hear an interview with Lars Brownsworth, the lecturer, on NPR's Hear and Now. Another interview is available on The Scriptorium.
In addition to this podcast, you may also find Byzantium: The Byzantine Studies Page interesting.
