I'm looking for some utility so I can download and rip videos from You Tube.

NjB

youtube-dl is the answer.

If you use firefox - Video DownloadHelper:
https://addons.mozilla.org/en-US/firefox/addon/3006/

Download helper is good but if you are on a linux box ,every time u watch video using your browser its already being download in /tmp.

There are some solutions, each with advantages and disadvantages:

youtube-dl, a command line script to download Youtube videos.
metacafe-dl, same as above but for Metacafe videos.
clive, a command line tool (with optional newt UI) for Youtube, Google Video (seems defunct at the moment) and Dailymotion.
VideoDownloader, a Firefox plugin which is supposed to work with more than 60 video sites (Youtube and Google Video are among them). The only disadvantage compared to the other solutions: you need to start Firefox + X11 (no pure command line usage).
UnPlug, a Firefox plugin similar to VideoDownloader, but with the advantage that it doesn't use the VideoDownloader web service (but rather figures out the video URLs itself).

There are some solutions, each with advantages and disadvantages:

youtube-dl, a command line script to download Youtube videos.
metacafe-dl, same as above but for Metacafe videos.
clive, a command line tool (with optional newt UI) for Youtube, Google Video (seems defunct at the moment) and Dailymotion.
VideoDownloader, a Firefox plugin which is supposed to work with more than 60 video sites (Youtube and Google Video are among them). The only disadvantage compared to the other solutions: you need to start Firefox + X11 (no pure command line usage).
UnPlug, a Firefox plugin similar to VideoDownloader, but with the advantage that it doesn't use the VideoDownloader web service (but rather figures out the video URLs itself).

There are also several userscripts for greasemonkey that do it. I use:
http://userscripts.org/scripts/show/25105

I have noticed that with Firefox on linux most flash streaming video is cached to /tmp with a Fla* prefix. I found if you copy the file into your home directory before navigating away from the page, you can view that video with xine or something and keep it. Otherwise the video is removed when closing the tab.
HTH.

+1

I just found this one, but I am going to look at that greasemonkey script too.

"Clive" from SlackBuilds.org will download most online videos.

MP4 YouTube Downloader - It's a plugin for firefox. I use a javascript button instead but works the same way
https://addons.mozilla.org/en-US/firefox/addon/9915/
xvst - downloads video from multiple sites including Youtube and converts them to *.avi by default.
http://slackbuilds.org/repository/13.1/multimedia/xvst/

If you are on Firefox...this has worked wonderfully for me to date.

for the tools mentioned already, here are my opinions of them.

Video DownloadHelper
unplug

(There are by now many choices for flash video ripping extension & addons for firefox these work the best IMO,
Wouldnt be surprised to see ports to other webbrowsers like google-chrome or other ext addons like above, of the 2
I prefer unplug, however sometimes these plugins tend to get left behind when keeping up with version updating of firefox,
so sometimes some versions will work in new versions sometimes you have to wait)


youtube-dl
greasemonkey script for DLing from userscript.org
Clive
xvst

(these others work well too, however for just youtube video ripping youtube-dl is sufficient, its a CLI tool)


and lastly the best tool for flash video ripping:


get-flash-videos

(the best of all is get-flash-videos IMHO, can do most any flash video website, and it keeps getting updated,
be it youtube or beyond you will need perl installed to this date its 5.8 atleast..., its a CLI tool and it works great)

Requirements:

perl >= 5.8.0
WWW::Mechanize
*Optional requirements (for support for certain sites):
rtmpdump
XML::Simple
Data::AMF
Compress::Zlib
Crypt::Rijndael

website: http://code.google.com/p/get-flash-videos

I mostly use online services if i want to save something from Youtube (like Keepvid).