I've been waiting for this plugin called "Video DownloadHelper" for a few weeks. Formerly, this plugin work out of the box on Firefox 2.0 where this plugin help me a lot on downloading videos from Youtube, TV3 website and many more which I would reveal on this post.
The main purpose for this plugin is to make it possible for Firefox user to download the Flash Videos (.flv) files by a point-and-click procedure. It's rich in features where else, it could make a download queue and download one by one your queued files until it finish eventhough you have close the Firefox.
And about couple of days ago, the new version of Video Downloadhelper has been release especially to support Firefox 3. The plugin working fine without any problem as far as I'm using it. So now I can download youtube files on point click.
For those who interested to try this plugin, you must have firefox installed on your system(luckily, all ubuntu OS used firefox as default browser). All you got to do is click on the link here, and the installation popup will appear, just click install and you are done!