Movgrab is a command-line movie downloader for sites like YouTube. It has no dependencies; everything that's needed should be there in the tar.gz package. Movgrab can connect through an HTTP proxy, can output the download to stdout for piping into another program, and can fork into the background to free up the console. When forked into the background, its progress can still be seen in a ps list.
Media Embed is a PHP class that can embed video and images from remote sites. It takes the URL of a page in a remote site that may have images or video and sends HTTP requests to that site to retrieve details about that media like the title, description, size, and thumbnail images. The class can also generate HTML to embed the given remote site images or videos in the current site page. Currently, the class supports retrieving information and embedding media from sites like YouTube, Vimeo, Facebook, DailyMotion, MySpace, MetaCafe, Revver, FiveMin, Clickthrough, DotSub, Revision 3, VideoJug, Blip, Viddler, Screener, SlideShare, Qik, Flickr, FunnyOrDie, TwitPic, and YFrog.
Videopian is a PHP class that allows you to get any kind of information (such as title, description, author, duration, or flash player URL) about a video hosted on a video sharing service, just by its URL. The currently supported services are Blip, Dailymotion, Flickr (API key required), Google Video, Metacafe, MySpace, Veoh (API key required), Vimeo, and YouTube.