I have released a course on Pluralsight called Agile Fundamentals that talks about Agile Software Development in detail.
The following video is a really good high level overview of Agile and Scrum. The video is by Ken Schwaber (One of the originators of Scrum). There are lots of Agile and Scrum overviews out there, but this one was particularly good. The video is only 20 minutes long, the sound isn’t great, but the content is spot on.
If you are trying to convince your manager / company / colleagues that Agile is a software development methodology worth following, then this is a good video to show them. The video talks a lot about responding to changes in a market place and how being Agile can help you maintain a competitive advantage.