I noted recently that the 26 part series by Vatican Radio – To the The Ends of the Earth (based on the Acts of the Apostles) – is still available to listen to (for those with Real Player), but not easy to access. Here are links to at least some episodes:
Note from 1/8/15: Well, it seems that most of the links (except some of the later ones) no longer work. Maybe some day Vatican Radio will release these in some format or give them their own webpage. If you have any connections, maybe you could ask for this.