This is an article from the Hardball Times. To be clear, it's not about pitchf/x changing the strike zone, but rather the strike zone changing and how we can measure it using pitchf/x data. I thought it was really interesting and that some of you might enjoy it.
http://www.hardballtimes.com/the-strike-zone-during-the-pitchfx-era/
http://www.hardballtimes.com/the-strike-zone-during-the-pitchfx-era/