In order to use the cmdlet first you'll have to grab the Microsoft Visualization Components from Microsoft Research.
If you don't want all the visualization components here is a zip file of just the treemap generator dll. Unzip it and put TreemapGenerator.DLL in your scripts folder.
Grab this file to get the scripts I demoed at the meeting.
Let me know if you have any questions or comments.
I'm hoping to do a full writeup for the blog soon.