You just type voicecommand -e to edit the configuration file and add any speech and the coinciding command. You can see all of the little nifty commands it can recognize just with my config file in the video. I use all of these pretty often. It is very mutable and works with lots of other programs.
The commands should be in the format speech==command. Ex:
music==xterm -e pianobar
Doctor Who==playvideo -r -f Doctor Who
I hope you will try this out and make some cool things with it. A video demonstration and Instructions to install are below in the links.
You can install with:
sudo apt-get install git-core
git clone git://github.com/StevenHickson/PiAUISuite.git