much simpler, google for a youtube to mp3 converter, there are loads ow websited to do it for you, you just copy and paste the URL in, and in converts it for you and offers the mp3 for download.
or
download realplayer (the free one) you can then click "download to realplayer" at the top of the youtube vid, and use its converter to get the full MP3, no need to mess with the long way recording stuff...