I just wanted to plug the php|architect (phparch.com) Magazine. It’s not too expensive and there are a lot of good articles each month.
One thing I plan on implementing to one extent or another is the PHP Clustering on Linux – comes from a set of articles by Joseph H. Kouyoumjian. Most likely I won’t use it exactly as described in the articles, but the idea will be useful for the load balancing approach on the new DFL web servers (and to some extent the imaging servers).
Another article worth looking at is the main feature this month (Vol 5, Issue 6): Total Eclipse of PHP Development: Banish your text editor to the dark ages! by Alexander J Tarachanowicz II. I’m already running eclipse for most of the editing needs, and it’s really something more people should consider, especially when faced with growing needs that your typical text editor can’t handle (or you don’t want to spend a load of change on other commercial IDEs).