From Microsoft Sharepoint Products andf Technologies Team Blog, a collection of links on security (webcasts, articles and much more), the author is Joel Oleson.
“Security is always important. I wanted to pull together a collection of all of the different security topics on Office SharePoint Server and WSS v3 across the Web Casts, Admin content, a couple of blog posts, and some partner materials. I’m sure I’m missing some, but I think this is a pretty good list.
You can find this collection here.