Unlike other similar services, YouTube Video allows only viewing video inside client's browser (YouTube's video player is designed to be used within your browser as an Internet experience), and currently you can't download our videos to your computer. But it can be easily downloaded and converted to the common "avi" format with Naevius YouTube Converter! http://www.naevius.com/youtube_converter.htm
There is another way of downloading YouTube videos. Here is a guide. You Will Need: Mozilla Firefox (Which can be downloaded here http://www.mozilla.com/en-US/firefox/) Video Downloader (Which can be downloaded here https://addons.mozilla.org/en-US/firefox/addon/2390) A Converter (Any free one will do) Guide To Converting YouTube Videos: 1. Find the video you want to download 2. In the bottom right hand corner of Mozilla Firefox click on the logo with the film strip and a floppy disk in front of it. 3. A box will come up 4. Just right click on the link and press save target as 5. Save it onto your computer wherever you like 6. Go to the folder wherever you saved it click tools->folder options->view and make sure the Hide extensions for all known file types is not checked. 7. Go to your file and rename the extension to .mpg 8. Then go to your converter and convert it to .avi
There is an even better program if you'd rather use a program than the grease monkey firefox plug-in. The program is called "Youtube FLV to AVI suite" its' made by a company called "Easiestutils" it's very easy to use and it can also capture and convert videos from : google video, myspace, ifilm, dailymotion.