Krista Tippett and the good folks at Speaking of Faith have put together an excellent program on the Azusa Street revival, featuring the wisdom Mel Robeck, whose new book on the Azusa Street revival I've been enjoying since the Society for Pentecostal Studies conference back in March.
Along with the program (which can be listened to online or downloaded as a podcast), the SoF site includes a wealth of resources related to global Pentecostalism. Great stuff.