Autodesk have released a batch file upgrader for Revit 2012. The program is intended to upgrade family content from previous versions of Revit to 2012.

You can find it here:
http://labs.blogs.com/its_alive_in_the_lab/2011/06/file-upgrader-for-revit-june-adn-plugin-of-the-month-now-available.html

Direct link:
http://labs-download.autodesk.com/us/labs/files/FileUpgrader.zip