There are a lot of video search engines on the Web, and plenty of free movies. Trying to find lectures given by actual instructors on classroom subjects is a bit tricky, even with all the video search resources available to us. That's where TalkMiner, a search engine focused on finding video lectures, webinars, and talks, becomes very useful.
Search for a subject, perhaps global warming, and TalkMiner will bring results that you can sort by relevance, title, publication date, addition date, number of slides, and duration. You can also search within "channels"; these are video channels curated by specific universities or think tanks. TalkMiner could be very useful for any student looking for specific lecture videos on specific subjects; or, if you're just looking for a bit of information, TalkMiner really makes it as easy as possible to filter through the chaff.
More ways to find high-quality content on the Web