Asbury Theological Seminary has a great page on iTunes University. You can hear great subjects on it, and entire classes on line.
I am providing you with an excellent series of lectures regarding the book of Revelation delivered by Robert Mulholland. He deals with “focuses upon the background materials of Jewish prophecy and apocalyptic, the structure of the book, its relationship to the other New Testament writings, and an examination of the perceptual framework which forms its imagery”
A must for all those interested in understanding this book that has caused so many controversies, but it’s a book of hope for the Church.
You can access the lectures here.