The 15 Minute History Podcast from the University of Texas is awesome!
I just listened to one about The Russian Empire on the Eve of World War 1. The narrator discussed Russian concerns on the eve of the war with Dominic Lieven, a professor at London School of Economics and Political Science.
Interestingly, one of Russia's major concerns prior to the war was Ukraine, which Russia saw as critical to its empire because of coal.
Other topics include the Trans-Pacific Slave Trade; Race, Slavery, and Abolition in Iran; and February Revolution of 1917. You can see a subject guide here.
Subscribe to the podcast in iTunes or Stitcher.
My thanks to AP World teacher, Bram Hubbell, for tweeting the link. He writes about other good podcasts in his blog which you can access here.