It’s a good week for app developers doing interesting things with Spotify’s mobile API. We’ve already covered SpotON Radio, but now Soundrop.fm has launched for iPhone too. It’s the work of a Swedish team, and is described as “the social jukebox app for Spotify”. It’s a lot like Turntable.fm, albeit without the avatars. People tap into virtual music rooms and listen to what’s playing, or step up to act as DJs themselves, choosing songs for others to listen to. As with SpotON Radio, users need an existing Spotify Premium account to use the Soundrop.fm app. Chat features are built around it too, so people in rooms can talk about what they’re listening to.