Apple and Google removed Grooveshark iOS and Android apps from their respective app stores because it "violated their terms" and all. Shrugging off those bans, the almost-legal online radio website has launched a new "soopersecret" beta for an online mobile interface written in HTML5.This new interface does not require a paid Grooveshark membership like the mobile apps did.
Currently, the web app is quite bare-boned. There is no login feature yet, which means that you cannot use your own playlists and such. It doesn't even have adverts in it.
The web app allows you to listen to any song you please, just like the standard version. The interface has three tabs: Search, Stations and Popular. The aptly-named tabs allow you to search for any song in the Grooveshark library, pick a genre station or look up currently hot songs.
I used it for a while on my iPad (running iOS 5) and it ran pretty well in Safari. Songs even played in the background and they were skip-able using the buttons in the multitasking bar.
The HTML5 app is compatible with iOS devices, Android 2.3+ devices, HP TouchPad, BlackBerry PlayBook and more according to the post on the Grooveshark blog. If you want to help out, you can test the web app on a device not listed in there and contact them.
Visit the HTML5 Grooveshark here: http://html5.grooveshark.com/