This allows you  to copy and use images, music, documents etc, as long as you attribute the work.

• Pics4Learning is a safe image library for education. You can use the copyright-friendly photos and images for classrooms, multimedia projects, videos or any other project in an educational setting.
• Google images search for pictures and add creative commons to the search term. Many images can be found this way.
• Many Flickr users have chosen to offer their work under a Creative Commons license, and you can search for photos.