Google and Istituto Luce have recently made an agreement to make all of the Istituto Luce's videos and images available through a dedicated YouTube channel. With more than 100,000 films and 3 million images, this promises to be an amazing resource for the documentation of Italian culture, society, and politics in the 20th century.
The Cinecittà Luce YouTube channel is here: http://www.youtube.com/cinecittaluce
For more on this development, see:
And for more on the Archivio Luce and access to a more detailed searching: http://www.archivioluce.com/archivio/