YouTube downloading question?

I saw several songs on YouTube this morning that made my jaw drop. I went on iTunes to see if I could buy one or two of them, but of course the songs weren't available on iTunes. :/ (if anyone's interested, they were In Christ Alone, Enchanted, and How Deep the Father's Love for Us (all by Owl City) and You've Got a Friend in Me and A Whole New World (piano covers by Kyle Landry)). So if these songs aren't on iTunes, is it legal for me to download them straight from YouTube?