If you are a user of Spotify Premium you will love this mod, SpotiPlay makes Spotify your default music player, so you can forget about the Music application that comes by default and carry all the music in the world on your iPhone with the music streaming service.
Also when executing the multiarea and slide the bar to the right (go to the page on the left) the music controls that now work with Spotify will appear, and the icon of music that stays there will also have changed to become a spotify button which will open your application.
You can download it free en Cydia, you will find it in the ModMyi repo. You need to have done the jailbreak on your device.
More information - HexaTasker: 6 icons in multitasking (Cydia)
And if I don't have a premium, what?