A pleasant and informative podcast I enjoy is called "Theology on the Go_." _Found on the _Place for Truth _website of the Alliance of Confessing Evangelicals, Theology on the Go is hosted by Dr. Jonathan Master who conducts a brief interview on a topic that should be of interest to those in the church. A natural conversationalist with an encouraging spirit, Jonathan does a wonderful job of keeping his guests on topic and asking questions that guide the conversation from belief to beneficial practice for believers.
Recently, Jonathan interviewed yours truly regarding the marks of the church. If you would like to take a listen, you can go here.
(Also, as usual when doing things like this, I snap my fingers afterward wishing I had said something else. In this case, it is two other resources regarding the marks of the church I would recommend. You can do no better than going to Francis Turretin's _Institutes of Elenctic Theology , _especially the Eighteenth Topic in Volume 2 on the church where he develops teaching on the marks in contrast to the Roman Catholic Church. Another shorter volume that introduces the marks in a helpful way is Daniel Hyde's Welcome to a Reformed Church: A Guide for Pilgrims.)