Download Youtube Videos
Recently I came across two nice tools for downloading videos from YouTube.
MediaSniper can download videos from YouTube or Google Videos in flv format. This tool doesn’t need an installation. Just double click the jar file, give the video url and that’s it.
JToothpaste can be used for downloading the video and at the same time extract the audio as an mp3 file. It can be downloaded from SourceForge, or a Java Web Start version is available here, which can be directly used from the internet.

Check out http://keepvid.com/
Allows to download from various video sites
But in keepvid, saving file is not that easy. it’s saving as html”, and one needs to know it should be renamed as flv. Also, i think there is no option to save only the audio, if you dont want video
JToothpaste is really nice! Very easy to use – And works on my Mac and Windows Machine!