All the content I upload on Newgrounds is free to use if and only if you make special arrangements with me, via PM. I try to check my messages at least once or twice a week if not more. Make sure the song you choose is able to be used. If you want to use my stuff, PM me first, and provide a linkable credit either back to this page, my soundcloud, or the song itself. If either of these rules are broken, I will have your content taken down.
If you'd like to use something not on NG from my soundcloud, discuss it with me.