You can use this bookmarklet on any page where there is a youtube video embedded.
Downlod.Now! <-- Youtube Download Bookmarklet* Just drag and drop the above Bookmarklet to your Bookmarks Bar.
* Then if you click that bookmarklet from any webpage with youtube video, The browser will generate video download options with many download formats.
* You may need to add the file extension ".mp4" or ".flv" to the filename when you save the file.
alsoread: Download Youtube Videos Vi@ Realplayer