This is an impressive video tutorial series on botnets by Corey Nachreiner
Botnets Part 1See actual malicious code and understand how it works. Corey Nachreiner explains botnet architecture for beginners, then builds a bot client.
http://www.watchguard.com/education/video/play.asp?vid=botnets1Botnets Part 2Learn how a bot herder uses his bot army for attacks such as Distributed Denial of Service, getting command line control of victims, installing spyware, and more.
http://www.watchguard.com/education/video/play.asp?vid=botnets2Botnets Part 3Learn the countermeasures, defenses, and Firebox tricks that render bots "Dead On Arrival" for your network.
http://www.watchguard.com/education/video/play.asp?vid=botnets3Botnet Source Code for OverachieversFor IT professionals who crave depth. This screen-capture video supplement to "Understanding Threats: Malware Analysis: Botnets, Part 1" examines bot source code line by line
http://www.watchguard.com/education/video/play.asp?vid=botnets1_overachieversAfter going through all of the above videos, supplement your knowledge with this great presentation by Richard A. Kemmerer.
How to Steal a Botnet and What Can Happen When You Dohttp://www.youtube.com/watch?v=2GdqoQJa6r4The presentation slides can be downloaded from the following link:
www.cs.ucsb.edu/~kemm/courses/cs177/torpig.pdf
Tutorials : Hacking Scenarios 
Hadnagy : [Article]-An Insider`s Look at the Social-Engineer.Org SE CtF at DEFCON
Editor-In-Chief : Free Webcast: Don't Pick the Lock, Steal the Key - PW Auditing with Metasploit
Links to cool sites. : Ninja-Sec Challenge You !
Tools : Nmap 6 Released
