Creative Commons/Public Domain Videos
In the same way, images are made available on the internet free of copyright, many videos are released. These sites provide videos with little or no copyright, in many cases, the videos are in the public domain.
Khan Academy
A rich collection of video tutorials on a range of topics.
Pond5
Pond5 is a site which provides a user access to thousands of videos which are in the public domain and free to use. Pond5 supports remixing of their content to create original content. The site also contains collections of audio files, images, and 3D models.
Moving Image Archive
The Moving Image Archive within the larger Internet Archive is a collection of over 3 million video files. Internet Archive categorizes its videos into categories which allow for easy searching. Certain categories such as Sci-Fi/Horror and Comedy Films contains feature length films that are currently in the public domain. There are also a series of limiters which allow a user to execute a more focused search.
Youtube
After you search for your topic on Youtube, you have the option to filter the results to those that have a creative commons license applied.
Vimeo
Vimeo is an online video sharing site that user can upload content for others to view. Vimeo also maintains a Creative Commons section which contains videos which are licensed under the various Creative Commons licenses. This section allows users to resue, remix, and share videos freely.