I recently wrote a short function to gather all available Com Objects from the registry and display the list of all objects using PowerShell. I wrote a short article on how this work on PowerShell Magazine, have a look at it here:

http://www.powershellmagazine.com/2013/06/27/pstip-get-a-list-of-all-com-objects-available/

The function is available for download in the Technet Scripting Gallery:

http://gallery.technet.microsoft.com/Get-ComObject-Function-to-50a92047