The White Horse Inn has a couple of excellent audio interviews with Sam Solomon on Islam. Solomon was formerly an islamic scholar who converted to Christ. Links to the mp3s here and here.
Also on the Nashotah House website (never heard of it before!) there is a lecture by Patrick Sookdheo, another former muslim and now anglican clergyman.
Both men extremely interesting and their messages eye-opening.
If all this is a little worrying, then you need to listen to Ashton Stewart at First Presbyterian Church, Columbia to hear what God is doing in Iran.