FullRip.net is a free online youtube video converting service, which allows you to rip and seperate audio(as mp3) from youtube videos and download them to your computer instantly. You can also download the video's in various formats and resolutions for you mobile device.
This add on adds a user friendly and non obtrusive button above YouTube videos which allows the user to extract the mp3 from the particular video or download the whole video in various resolutions for free! Its as simple as 1-2-3! Give it a try!