Playlist Hunt - Playlist Hunt is one of the best applications for Apple users to get the best music through it.
keezy - A colorful soundboard. Play with music.
Book Playlist - Collaborative music playlists for your favorite books
Figure - Propellerhead creates world-class software products and services that inspire music makers and provide the foundation for a worldwide creative musical community.
Musicon - An interactive music-making machine for children
Splice - Music creation, collaboration, and sharing made simple.