A while ago I recorded four security screencasts for MSDN UK. They are part of their Nuggets series which I always liked.
Main Page:
http://www.microsoft.com/uk/msdn/events/nuggets.aspx
- Client Certificates and ASP.NET (watch)
- Impersonation (watch)
- Protected Data (watch)
- Storing Passwords (watch)
leastprivilege.com 