The bitflux blog has a new post today with a note about the post of the slides from chregu's talk at AapacheCon:

My first talk here at ApacheCon is finished. The slides are online here. Now food :)

The talk covers some of the new things dealing with XML handling in PHP 5.1 - SimpleXML, better DOM support, XMLReader's inclusion, etc. It seems to be pretty comprehensive, even getting into a bit of code later on as examples.