Domain-restricted videos in YouTube
Google Apps users who use their Google+ identity in YouTube will now have the option to post videos that are viewable only by others at their domain. Domain-restricted videos can only be viewed through the web UI at this time. You’ll see a field under the “Privacy Settings” drop-down menu where you can add your domain to the list of people who have access to view the video.
For more information:
Google Apps for Business, Education, and Government