how to download videos from youtube to watch when not connected to the internet

I found this great little plugin for Firefox browser. it's free and
you can queue up multiple download of youtube movies.

http://www.sothinkmedia.com/web-video-downloader-firefox/

after installing, you just go to a youtube video, and click on the
icon to download the file..choose where to save and you're done after
a few minutes of downloading.

You need VLC media player to watch flv videos...it's also free, for
pc and mac.