I have used YouTube (like everyone else),TeacherTube (which I love) and now have just found SchoolTube.
This web site was launched some time ago and is a teacher moderated video sharing website.
They are dedicated to supporting educational institutions and have a range of videos for educators to show how a range of ICT tools and software can be used in the classroom to enhance the thinking and learning as well as motivating the students. Teachers are able to share concepts, ideas and lesson plans with others.
There are various channels you can use starting with the free channel for teachers. There are other options which will cost the school e.g. a Premium channel costs $US495 a year.
I was disappointed to see on the main page of the site showed this video (title). I am not sure if the teacher moderated this video. While I know it is fashionable not to correct a student's work it is possible to discuss the spelling of something like this before it is uploaded to the site.