A while back i blogged about how to ” Download video and mp3 from youtube with Greasemonkey script” but that script is broken and every other script i tried stops working after a couple of days.

There is however an alternative to the scripts, a Firefox addon that seems to be working just fine: YouTube to MP3 .

This addon lets you extract and download mp3′s from Youtube, MyVideo, Clipfish, Sevenload, Dailymotion, MySpace as well as video files.
Enjoy it!