How to download movies from YouTube

Brian writes, I just started watching videos on YouTube recently, but I can’t figure out how to save them to my hard drive. Is this possible, or am I stuck bookmarking the pages?
YouTube uses Flash video to playback movies on their site. In addition to being universally supported on most computers, one of the many benefits of using Flash from a video creator’s standpoint is making it harder for people to download the movies. It’s not impossible and depending on how the Flash movies are played, you can sometimes simply dig in your Temp directory for the file because the server actually downloads the entire movie to your computer during playback.

For YouTube movies, the easiest way to download the file is with some free software. I’ve recommended other solutions in the past, but the current method I find easiest is to use RealPlayer SP, which includes built-in support for downloading YouTube videos.
If you find a YouTube video you like, RealPlayer SP automatically downloads the file and saves it to your hard drive. A little button like the one pictured below appears, which you click to download the video to your PC.

RealPlayer SP also converts YouTube videos so that you can play them on your iPhone, iPad, or any other favorite video player.
Since RealPlayer SP is also a video player, it can automatically play YouTube videos downloaded to your desktop.