If you can access it and record it for personal use, then it isn't stealing. If you reproduce it or send it out again or in some way profit from it, then you're no longer in a personal use question. You can record television programs to watch again, whether with VCR or DVR, etc., and I would argue this is just the same.

I use a web site where you plug in the URL of the video you want to save and then give it a name and save it. http://keepvid.com is the place where I first saved Susan Boyle's performance on YouTube so I could put it in my mp3 player. It worked fine.

SRS