The Economics Network have put together a briefing document on how to find audio, video and images for use in economics teaching, which can be a tricky area, given the strictures of copyright and the poor way standard search engines handle resources in different formats.
For example, this recent audio interview available from Warwick Podcasts on the future direction of multilateral trade would be invisible to search engines, if it were not surrounded by descriptive text explaining what it is.[audio:http://www2.warwick.ac.uk/newsandevents/audio/wcreport.mp3%5D
Similarly this extract from Fora.TV featuring Paul Krugman talking about the income inequality and the American Middle Class is arguably more visible to users via YouTube than it is from the original site.
… and while image searching is available from major search engines – are the results really more useful than looking at a specialist source? Especially given that copyright means that it would be unwise to reuse many of the images, such a search returns.