As of this post, there is an audio series by R.C. Sproul on Roman Catholicism and it is being given away.
It’s a very good starting point for any Protestant who doesn’t know much about the RCC, or who doesn’t understand what the fuss between us is all about.
Let me point out that the series is NOT about how the RCC is wrong, but simply about key RCC doctrines and their developments over the centuries. Sproul takes pains to be not only fair, but accurate. He often quotes papal encyclicals, sometimes tamps out Protestant reactionary fires, and generally draws the map. I know there are several (or perhaps many) Roman Catholic readers of my blog. I’d be interested to know their thoughts.
My endorsement is worth every penny you paid for it; which is convenient because it matches the series’ price.