Get the Whitepaper called An Analysis of the Skype IMBot Logic and Functionality.
You can download it from the following link: https://packetstormsecurity.com/files/download/87297/skypeimbot-analysis.pdf
Source: https://packetstormsecurity.com/files/87297/An-Analysis-Of-The-Skype-IMBot-Logic-And-Functionality.html