Directly from Dave (ReL1K) Kennedy's Blog:
I’m proud to announce the release of the Social-Engineer Toolkit (SET) v1.2 “Shakawkaw”. This version of SET does not include any new attack vectors however does incorporate two new exploits from Metasploit, has some bug fixes, but most importantly introduces a significant step in allowing individuals build and automate additions onto the toolkit. I’ve also updated the User_Manual.pdf which is located under the readme/ directory and the Metasploit Unleashed course should be updated with the latest content. This new version centralized a lot of the code in a “core” functionality that will allow you to build whatever you want to into SET now. In this version it introduced the core library modules and the ability to add third party modules into SET.
Full blog post:
http://www.secmaniac.com/january-2011/the-social-engineer-toolkit-v1-2-shakawkaw-released/Don