Technically, downloading and converting content from YouTube could be considered copyright infringement, a federal crime punishable by both a financial penalty and jail time.
But from a purely theoretical and scholarly POV. I would suggest that this wold be a two part process the first would be to download the embedded FLV file from youTube.com and then convert the FLV into an MP3 format. If I were going to do this I would download a plug-in for my browser (I use Firefox) that is designed specifically to download video content from sharing sites like youTube. I would probably use one like “Download helper” or “UnPlug” which are specifically intended to perform this function. Once I have the FLV file on my hard drive I would use a file converter like Riva’s FLV Encoder or one of the programs on Aspyder’s list to convert it to an MP3
