There’s a 3rd party Grooveshark app available in the Marketplace now and it’s free. Truthfully, it’s nothing special. In fact, it’s just the Grooveshark HTML5 site wrapped in an app (which works in browser on WP – if the tabs are finicky just tap and hold to open in a new tab and they all load). So why is this noteworthy? Because Microsoft has pulled past Grooveshark apps (similar to the way iTunes treats it) and it was presumed to violate the Marketplace certification. My gut is that the certification team missed it but maybe this does mark a change in Microsoft’s views on Grooveshark.