Here's a spunky blog I've been reading recently: By Whose Authority? I've seen some good posts, and recommend a visit. I've left a few comments in the Cyril of Jerusalem entry.
Here's a fun little thread from Catholic Answers: Are there scripture passages the Church has defined?
I've been interacting with a guy over on the CARM boards about Luther and authority. The recent discussion begins around page 36. Trust me, you don't want to trudge through pages 1-34. The only reason I decided to interact with the person who started this discussion, was that I was able to corral him in to posting 100 words at a time. Otherwise, he'd write a small book in each post. My interactions with the topic begin around post 704.