I use a freeware program called YTD Video Downloader, and it allows me to download videos vrom YOuTube to my hard drive.
It then has a convert function that allows me to subsequently convert downloaded clips to various formats, including different video formats, as well as conversion to several audio type - MP3, WMA, etc.
I use this all the time, then import the converted audio files into Sonar.
Here is a link to their site - just say no on any upgrades (they cost money) and be careful not to allow additional tool bars to get installed (there will likely be a checked box that you have to remove the check to prevent some tool bar from getting installed). Other than that, the program works GREAT and I can stack up a bunch of download requests, so I may setup 20-30 videos to get downloaded one after the other, while I go back to sleep or cooking or whatever.
Here is that link:
http://www.youtubedownloadersite.com/ Bob Bone