Here is a link from our pals over at cnet for a free youtube to MP3 converter.  The user can extract and download music from YouTube movies and save it to MP3 files on your PC.  The download gets a 4 out of 5 stars from CNET users and CNET editors.  The site also provides a brief description of the download and how to use it.  Operating systems include Windows Vista and Windows XP.  Enjoy!