As we launch our study of the book of Revelation here are some resources I have been using that have been helpful in studying and enjoying Revelation:
BibleGateway.com has a number of listening options.
Free Online Commentary & Bible Study
Prof. Vern Poythress has 2 wonderful resources available online for free!
If you want to dig deeper and wrestle with works that are a bit more technical and scholarly then here are 2 commentaries to consider purchasing: