i personally think it's beautiful and perfect for New Moon. i would imagine the song playing in the time right after Edward leaves, and before Jacob really comes into play.
Yes I have heard it! I love it!! It's so beautiful, I fell in love with the song the first time I heard it.
I would put the song either when Edward leaves and Bella is lost in the woods, confused and all or when Bella jumps off the cliff and she's hearing Edward's voice. One of those scene. I really hope they put that song on the soundtrack!