Grooveshark, the internet music service, has always tried to have an application for iPhone users. It started out being available only via Cydia for jailbroken devices, until the App store approved them. A week later, Apple got a complaint from Universal Music Group and had to remove the Grooveshark app prompting Grooveshark to go back to Cydia.
The application is now available via Cydia with several improvements. These include retina display graphics for iPhone 4, multi-tasking support, a function to save radio sessions that users have listened to as well as save user-made stations, and pre-built genre based radio stations.