"Audacity" will do that. I believe there is a recently updated version now. You may have to download the manual to set it up the way you want it.

If you happen to use Firefox, this extension is kinda nice.

It adds a dialog like this:
{{gwi:1467236}}(Click to view full-sized)

I'm sure there are other addons and methods that work. I just somehow stumbled onto this one, it worked, so I stuck with it.

It should work for you as long as you haven't joined the YouTube HTML5 trial.

Youtubedownload works great for downloading and then converting to MP3. I also use the Firefox extension for downloading the videos.

Jean

Here is a link that might be useful: youtubedownload

Okay, Jean, I downloaded your link and went to try it, but forgot so many videos now have ads before them. How can I skip the ad or edit it out? Also, when I want to convert it, it asks which file. There are so many to choose from, which one do I need?

Thanks everyone, I will try all of them out to see which is easiest, this was the first try.

I don't think you can remove just the ads unless you would use an audio editor.

When it asks what file you want to convert, browse by clicking on the folder just to the right of where it says "Select the video file". I like using the youtubedownloader to convert, because I can download all the videos and convert later at my leisure. For the most part, I do use the Firefox add-on to download. Just easier when you are on the youtube page to click "download".

HTH, Jean

Tickman suggested Audacity. Have you tried it. You don't have to download the video. Just play it and record the sound with Audacity. Then you can edit out any part you don't want before exporting it as an mp3.