Ewald pointed me towards two of the talks this morning that were given at the International PHP Conference this year, held in Amsterdam.

The first, by George Schlossnagle and Sterling Hughes, is about creating High Performance PHP. Basically, this is creating an application that works well, and works within the time constraints you're given for it. There's some great details on how scripts are parsed and what steps need to be taken to get your scripts optimized in this process.

On of the other talks was by Sterling Huges and Harald Radi, talking about ADT for PHP. For those that don't know: the ADT extension is standard set of abstract data types, including heaps, balanced binary trees (AVL variation), binary trees, and graphs. It can be used to increase performance as well as make result sets easier to work with.