does anybody knows how to download videos from youtube.com ?

Answer 1

There are programs you can get online (usually not free) that allow you to record streaming video:

http://www.download.com/ZD-Soft-Video-Recorder/3000-2194_4-10547979.html?tag=lst-0-9

http://www.download.com/Music-Video-Downloader/3000-2166_4-10449198.html?tag=lst-0-10

http://www.fox-magic.com/mc_gb/record_streaming_video.html

Changing the file extension doesn't work - I just tried it out of curiousity.

Answer 2

the video you watch on youtube, is saved on the ie tmp directory, it's saved as the url you pick..
example:
the video on http://www.youtube.com/watch?v=8qH0suPFdzk
check the ie tmp, there's a file named "get_video?video_id=8qH0suPFdzk"

just copy that file to any directory on your site, and change the extension to swf o flv..(the file is copy as get_video).

if you want to watch it on flv use http://flv-player.softonic.com/ie/44422
or you can move your swf file to any other format, like wmv, mpg o avi (you have to use a video editing program)