Tutorial Paper Piecing

OK I'm trying to learn what is this "Paper Piecing"

I found this neat little video

http://www.youtube.com/watch?v=L0HoU0Sw1iU

Listen to the song also oh my I will be humming that tune all day!!:)

Here is another awesome Tutorial

http://www.youtube.com/watch?v=I4p-vpLScRw&feature=related