Usually, I tend to think of Youtube videos as teaching material for EFL courses. Recently, I've discovered a number of videos aimed at teachers. I will share a few of these here:
Macmillan has over 30 videos for ELT teachers, including some excellent presentations by big names such as Scott Thornbury and Lindsay Clandfield:
On another website, there is a nice series of short videos of Zoltan Dörnyei, with the title "Motivation in the language learning classroom DVD":
This was a wonderful discovery for me, since I'm currently reading his book, Motivation Strategies in the Language Classroom. The videos are helping me review the contents of his book.
The University of Oregon has a series of videos titled Shaping the Way We Teach English, introducing a series of important topics, such as contextualizing language, building language awareness, and integrating skills. Here's module 1:
Madridteacher has some some very clever tips on teaching. Here's his video on how to teach interesting English classes:
These final two are about language in general. There's an entertaining video of Steven Pinker talking about language at Google:
Finally, here's a video of Bill Labov talking about American English: