A very little history
Once upon a time, someone at somewhere went to
do something. He was very, but very crazy for videos. He everyday watch
streaming videos but he never knew how to download them. Anyway, some day he was
thinking under of a tree with a notebook in his hands, and suddenly a little
fruit was crashed in front of him... maybe it was a coconut. After, he said:
"Damn!", and immediately after he thought: "Not 'damn'... down. Download!". So,
he discovered how to download them with a very simple kind.
Did you like to download streaming videos but
you don't know how? Now it's the chance! With a simple software called "YouTube
Grabber!", you can download the streaming videos from them URL's. Confusions?
Nope! It's very simple software. Unhappily I don't know if it works with another
sites (like Google Videos, IFilm, etc). This program was tested just with
YouTube site, but... if you have courage to test this software in another
website, do it!
So, let's see how it works:
1) Download the software clicking here
2) Open it (it doesn't need installation)
3) Paste any YouTube's URL in the field and press 'Grab!'.

4) Now, just wait until download will be completed.
PS.: the file will be downloaded with a ".flv" extension, but you can convert this to another one, like MPEG, AVI, etc.
To convert the file:
"A software called "SUPER Fever Link"
is ideally. It supports a wide variety of input/source file format to play or
encode (to & from) without any additional third party software: - Video format:
3gp (Nokia, Siemens, Sony, Ericson), asf, avi (DivX, Xvid, MPEG4, MSmpeg4), fli,
flc, flv used in Flash), mpg (Mpeg I or Mpeg II), mov, mp4, ogg, qt, rm, str
(Play Station), swf (Flash), viv, vob, wmv - Audio format: ac3, amr, mp2, mp3,
mp4, ogg, ra, wma SUPER supports the conversion (encoding) to most of the above
mentioned formats. SUPER provides a variety of video codec selection with every
file format conversion (encoding). SUPER provides a variety of audio codec
selection with every file format conversion (encoding)."
Solution is here. Download and install! This software is very easy and your grandma' can work it.
But if you are not interesting for the quality of the video, you can watch it in flv (flash). You must download the "FLV Player". Click here to download and after install it.