(HT to Mark Shea) - Librivox has produced a recording of Against Heresies by St. Irenaeus. Here's the summary from Librivox:
St. Irenaeus, Bishop of Lyons, describes several schools of Gnosticism which were prevalent among pre-Nicene Christianity. He then refutes these beliefs as heresies by contrasting them with what he describes as catholic, orthodox Christianity. Against Heresies demonstrates that earliest Christianity was a fascinating and diverse plethora of beliefs, debates, and schisms. (Summary by JoeD)There's too much audio for me to hard link, so go there and get it yourself.