for youtube, you will need to apply for a partnership account. your videos have to be original though, so no copyrighted content. and you have get a good audience meaning your videos get thousands of views.
If its a whole site dedicated to videos, you're going to be pushed not to get caught out on copyright infringement issues. The larger your site the more trouble you may have.
video sites allowed just make sure there is no auto refresh of page/video as it increases page views. also no XXX content.