SingStar with new features. A free update coming this June will add online battles to the long-running karaoke franchise. With online battles, you'll be able to send invites to PSN friends and challenge them to songs both players own. With the PlayStation Eye, you'll even be able to broadcast a video stream of your performance to your opponent.
If you're interested in beta testing this new mode, then submit an application here. You must have a European PSN account to sign up.