Copyrights law on video and audio as well allows you to copy 3 minutes of total video & audio to be used on any kind of presentations you wish like (PowerPoint Presentations or video presentations) for education purposes and other presentations as well.

I don't know any websites that specifies this, but I guarentee you what I just said above is the copyrights law which I have recently aknoledged at a seminar on copyrights laws. I am sure you might get this information on google,com or a quick call to the FBI (Federal Bureau of Investigation) office will confirm about this issue.

J. Bond