Backpack TV: Backpack.tv pulls from various sources to create a highly curated library of education videos organized by academic subject and detailed topic. Many of the videos are linked to topics from popular textbooks, a real bonus for finding just the right video. Videos can be user-rated.
This is another web tool that lets users select a specific portion of a video to play. The difference between this tool and the ones mentioned above is that it only lets you specifiy a start time but no end time.
There are some videos where all you need is a small portion. When I am designing Moodle courses, I will sometimes only need small parts of videos to embed. Welcome Tube Chop. Take the URL of the video you want to chop and trim both the beginning and end to what you need. You can then share it via a link or embed the chopped video on your site or page.
There may be times you need a series of videos and they would be better off watched one right after another. Drag On Tape does just that. Insert the videos via their YouTube URL. You can trim to the sections you want, add another video and another and another, creating your own personal mixed video that you can then post via a link or embed.
"P3 From YouTube Flash Video
ListenToYouTube.com is the most convenient online application for converting YouTube flash video to MP3 audio. This service is fast, free, and requires no signup. All you need is a YouTube URL, and our software will transfer the video to our server, extract the MP3, and give you a link to download the audio file. "