Download youtube video via ubuntu 10.04 (lucid lynx) is become easier, there is an application called youtube-dl which help us to download directly youtube video through a Ubuntu terminal. Youtube-dl is small command-line program to download videos from YouTube.com, youtube-dl is not defaulty in Ubuntu so it's required to install first before we use it. here they are step by step using
    1. Open your terminal type 'apt-get install youtube-dl' to install.
    2. Open youtube then find the video you want.
          example :  http://www.youtube.com/watch?v=WGf4i_kxqRU
           3. Open terminal again and type 'youtube-dl http://www.youtube.com/watch?v=WGf4i_kxqRU'
                synopsis : [youtube-dl] [url-address]
        The same way can be implemented to download video from metacafe and nicovideo.jp, but we use different application. To download video from metacafe we ca use 'metacafe-dl' then 'nicovideo-dl' to download video from nicovideo.jp.