Packt Publishing has just released the book "Plone 3.3 Administration", available here. The book is targeted towards administrators, not developers, and offers a great many step-by-step buildout instructions for adding functionality to your Plone site. (For those unfamiliar with Buildout, it's the preferred mechanism for downloading and installing add-ons to Plone.) The book covers many topics that will be of interest to administrators, i.e. caching, front-end load balancing, security, etc. One caveat-- don't expect a lot of overview material on any of these topics-- there's enough here to get the add-ons installed, but figuring out the high-level overview of these components is up to you.