Follows are some of the talks I have already gave, with their slides.
Slides for the "Linux Development Tools" lecture I have given at the "Go-Linux" event on April 10th, 2003 (Hebrew PDF)
Installing a secure Linux server (English PDF)
A three part lecture given at Haifux about code security, what are vulnerabilities and how to exploit them. The lecture also had a frontal step by step development of a simple arbitrary command exploit for stack overrun and format string vulnerabilities.
An article (Hebrew) explaining why Linux won't be vulnerable to viruses, even if it becomes as common as Windows (PDF).