John Coggeshall has linked to the download of the slides from his latest (and very popular) conference talk - Top 30 Scalability Mistakes.
For those of you who are interested, you can download my slide from the tutorial I gave at ApacheCon this year. This is a very popular talk that I've been giving all year -- and this is by far the most extensive version of the talk yet.
The slides cover topics like system scalability, PHP scalability, database scalability, web server scalability, and using these tips to optimize your application.