This is a two step process currently, you have to define the work item in Team Foundation Server and then go back to PowerPoint to connect the workitems.
I am using VS 12 RC Premium, it should work in VS 2010 Professional or Ultimate, but not Express, and you need to have either Team Foundation Server or Team Foundation Services (the free internet version):
Now you can link to the storyboard, but be on a PUBLIC location, for some reason when I browsed to the location in the file explorer on my client machine it kept bringing up the file on my client not the skydrive. I went directly to the skydrive and did a share, it worked fine.
Once you get this linked, when changes are made to that specific file then your Team Foundation Server keeps the link and you have the file stored in a manner that you can use for collaboration.
In the next blog I will detail how to generate the tasks that you can hook the work items to the Storyboard. I have been told that the feature you may have noticed in the earlier versions of storyboard: Add Work Items is not in this branch of the Storyboard tool. (As of the post date of this blog.)
So you will have to create tasks generated in the storyboard and then attach them to the various items in the PowerPoint Storyboard.