I need a youtube video to mp3 desktop app or firefox plug in created

i need a youtube to mp3 script that uses the ffmpeg library like so many sites out there right now... we need to able to enter a youtube id, have a progress indicator for when the file will be ready, and then a link to download the mp3... just like the following sites.. video2mp3 (dot) net keepvid youtube-mp3 (dot) org i know a lot of you programmers have this script ready to go... The new spin that I would like to put on this would be to make this a desktop app or firefox plug in where you can Right click ANY video, and in your options there is an option to rip the audio off of it. whether it's from you tube or an online video that was put up on someone's blog that is self hosted . right click on video ---> options screen comes up that asks : convert to mp3 ---> pick where you want to save the mp3 file on your computer.