You tube is a very useful source for a history teacher. There are really some many great things posted by others with more experience in particular subjects, such as John Green. He does a series of videos called "Crash Course in World History" where he gives 10-15 minute overviews on particular subjects. He uses both his own understanding of the topics, and cartoons entertain and give students the imagery of what happened during that time period or event. Here is an example of his crash course on the agricultural revolution.
Here is another video on the french revolution which we watched in my class back in January
Copyright laws have always been fishy to me. Back when I was in school, I remember being afraid of accidentally plagiarizing on every paper I wrote. I would use other sources for research, and include bits and pieces in order to support my own thoughts. I thought as long as you cited the source you were in the clear,but apparently that's not always the case. Now as a teach I have to worry about fair use and copyright laws that are quite similar. Until last year, I thought that only books or writing samples could be copyrighted, but now I know videos, photos, music, and even dances can be under copyright laws too. You must make sure that you keep in mind the nature of the use, purpose of the use, amount of the use, and effect on potential markets.