In my view the online video editing tools that are available at the moment have not yet reached the stage where they can compete with desktop software such as PowerProducer/Director. That said, as bandwith increases it will only be a matter of time before we are editing videos online. The tools that are listed below therefore tend to focus on how you might use existing videos in your teaching. You should also look at Whiteboards and Collaborative Tools for further screencasting software and Presentation tools where you will find tools such as Vimeo.
1.
Jing - This is a free download which could be very useful for teachers. After installing a yellow circle will appear on your desktop which enables you to make a screencast of anything that is on your screen. This tool is very easy to use and works really well. The finished video can be saved on your own computer or uploaded to the Internet for others to use. There are many uses for this tool from recording a demonstration for students to recording feedback for computer based work. You can use the tool to grab flash videos from the net but the sound is not quite right. There are better tools to use such as those below
2.
Replay Music/Media recorder - This tool is designed to record streaming media from the Internet. You can record audio or video from anysite just like using a video recorder or tape recorder to tape from the radio. The tool can be used for free to download 25 songs and then must be purchased for approximately £10-£20. I have used it to create audio files of streaming files such as lectures, I haven't tried for video as there are other free tools which work very well.
3.
Screencast - Having obtained your media or created audio or video files you will probably want to share them with your students. Screencast is a free service for hosting your own videos...your own personal Youtube. This may be useful if your school website blocks youtube as you have total control over what is posted. You can also embed the video from Screencast into your own webpage as I have done below.