Java applet based video downloader script is available at vidfetch.com . Here you can get standalone video downloader script which can work as video converter script . PHP script are also available for the same and related purposes.It supports several sites including popular sites like YouTube, Dailymotion and Metacafe etc. these scripts also work as a video downloader script. video can be converted and downloaded into several popular formats such as FLV ,MP4 , MP3 etc.
vidfetch.com supports several popular sites . See this link http://vidfetch.com/updates for vidfetch supported sites