Here you can find links to some of the resources I have used to research the topics for episodes. There are also links to other interesting sites.
The History of the Papacy Podcast is a proud member of the Historypodcasters.com network. This website has a directory of just about every great history podcast out there. You can also listen to the History Collage, where your favorite history podcasters get together to discuss a topic, from each of their unique perspectives.