YAAK stands for Yet Another Application Kit. It's a set of tools to help developing enterprise applications in python.
yaak.cmdline is a package from the YAAK toolkit that helps you build console applications in an object-oriented way.
You should have easy_install (from setuptools, or something equivalent) installed on your system. Just type easy_install yaak.cmdline on a command prompt to get the YAAK's cmdline package installed.