I gave three talks at this year's phpworks conference. The most popular was PHP Security by Example, a talk that consists entirely of exercises. This approach is unique in the sense that the focus is on first exploiting vulnerable code and then fixing it. I think seeing how easy some exploits are gives people a better appreciation and understanding of the safeguards.

The slides are available in PDF and Flash format:

• PHP Security by Example (PDF)
• PHP Security by Example (Flash)

I'll post the slides to the other talks soon.