Videodownloader, a Firefox extension will allow you to download videos from Your Tube.......I might be wrong, but I think that if you post a video on YourTube, you agree that is in the public domain.
"YouTube respects the rights of copyright holders and publishers and requires all members to affirm that they hold the copyright or have permission for the content that they upload. If we receive a notice that content infringes another party's copyright, the member's account may be terminated and the content will be removed from YouTube."
Nothing stated anywhere that the posted videos become public domain.
you can use free online-scripts like the one on www.keepvid.com as well.
Simply paste the Youtube link into the little frame and click 'download'.
A download of a .FLV file (= flash video) will start. With a special FLV-player you are able to play those files back. There are many freeware players available.
Easiest way to save YouTube stuff is to go to your temporary internet files...usually in a place like:
C:\Documents and Settings\Jim\Local Settings\Temporary Internet Files\Content.IE5\8X4NO1QF (the last folder location could be any one of several temp folders that IE creates).
Sort the files there by size and you'll see files for videos you've already watched on Youtube named "get_video[1]." The trick is that you must watch the video until it's fully buffered in order to get a ful file. Then rename the file with the extension "flv"
You'll need a player that can play these flash videos and there are a few you'll find for free if you google "flv player."
If you want to use the file in Vegas you'll need a file converter that can handle flv files such as "Total Video Converter."
Another option is to use a program like FRAPS or Camtasia to simply grab the video direct to a avi file.