This is an impressive  video tutorial series on botnets by Corey Nachreiner

Botnets Part 1
See 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=botnets1

Botnets Part 2
Learn 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=botnets2

Botnets Part 3
Learn the countermeasures, defenses, and Firebox tricks that render bots "Dead On Arrival" for your network.
http://www.watchguard.com/education/video/play.asp?vid=botnets3

Botnet Source Code for Overachievers
For 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_overachievers


After 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 Do
http://www.youtube.com/watch?v=2GdqoQJa6r4

The presentation slides can be downloaded from the following link:
www.cs.ucsb.edu/~kemm/courses/cs177/torpig.pdf

these are nice vids! they really know how to explain a specific subject so everyone can understand! i didnt know about the presentation slides so thanks for that! great find!

great set of vids very informative thank you