I have been catching up on my blog reading and there has been some good stuff posted out there lately.
Over on Coach Hoover's Blog there is an excellent series on defending the flexbone option with the 4-3 in posts on position play for Corners, Safeties, OLB's, Mike, DE's, and DT's.
Also Duece (of Coach Huey infamy) has a new blog and continues on the topic of defending the flexbone.
If your are interested in addressing the flexbone from an offensive perspective or just want to spy on the opposition check out http://3backoptionfootball.blogspot.com/
Smart Football wrote about the evolution of fire zone pressure (here) and Brophy discussed further the Caper's Nickle package (here).
Another pressure related post from Brophy focused on new Texas defensive coordinator Manny Diaz and his fire zone package (here). I think this post is fascinating because of the contrast between Diaz's fire zone teaching model and that of other fire zone coaches.