One of d coolest n easy trick. . :) you can also use it on cell. .
- open the video which u want to download
- go to address bar
- add ss (before youtube.com)
e.g : video link is http://www.youtube.com/watch?v=WKCXU5SPums
now add ss http://www.ssyoutube.com/watch?v=WKCXU5SPums
this will open a page under download links you can select and download.
