Playlist Machinery - Tools that help you create & organize your Spotify playlists
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
podsync - Simple and free service that lets you listen to any YouTube or Vimeo channels, playlists or user videos in podcast format
Kobo Audiobooks - Experience the joy of being told a story