Playlist Hunt - Playlist Hunt is one of the best applications for Apple users to get the best music through it.
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
Book Playlist - Collaborative music playlists for your favorite books
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Musicon - An interactive music-making machine for children
Audioship - Upload audio to YouTube or Facebook