Viruses don't harm, ignorance does!
Viruses are the coolest thing in the entire universe. They're the ultimate form of cool coding techniques. Programs that can print their own source code (quines) are always beautifully written works of art.
Note that I'm not a supporter of malicious viruses. While things like Stuxnet and other APT viruses may be skillfully written, and utilize interesting and revolutionary techniques, their source and malicious intent puts a bad taste in my mouth. I'm a fan of virii which are written for fun and as a hobby.
Below you'll find some pages of mine that have to do with the subject, along with some of my favorite external resources, books and websites that cover the topic.
While this book may be quite old (Almost as old as me, in fact!) it's still one of the most recommonded books when learning about viruses. It's a comprehensive book covering many different types of viruses, how they work, and even specific source code. Nothing this comprehensive has been published ever since, with most books these days either delving deep into one subtopic or glossing over the subject as a whole.
This is some of the best personalized content to come out of the VX scene. hh86 and SPTH conducted a series of interviews with famous old-school virus writers over a period of a few years. Famous names like JPanic, roygbiv, and even Peter Ferrie were interviewed. The files give a more personal look into the lives of some of the top virus writers, with information on how they started, what their inspiration was, and what they're up to these days. Cool stuff! (hh86 and SPTH are also VX scene OGs, so Google their names and check out their work as well! :) They're two very cool dudes.)
Many of these projects were done for fun and out of a love for programming. They may not be polished or even complete. If you'd like more information about a given project or the process used in creating it, you can always contact me.