Pandora iMessage App - Say it with Pandora — Send and receive songs in iMessage
Magic Playlist - Get the playlist of your dreams based on a song
Pandora Premium - On-demand music. Pandora's answer to Spotify.
Spotalike - Spotify playlist with similar songs, according to Last.fm
Pandora - Pandora Radio is a free (ad-supported) internet radio founded in 2000.
Playlist Machinery - Tools that help you create & organize your Spotify playlists