20v - Create a custom music channel based on a single song
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
Tune My Music - Transfer Playlists Between Music Services
Playlist Machinery - Tools that help you create & organize your Spotify playlists
Hermes - Pandora Client for OS X
Pandify - Convert your Pandora 'likes' into Spotify playlists