UltraStar Deluxe is a free open source karaoke game for your PC. The gameplay experience is similar to that of the commercial product SingStar™ by Sony Computer Entertainment, which is exclusively available for the Playstation®.
Unlike SingStar™, however, UltraStar Deluxe allows users to create their own songs and sing them on their PC.
Get SingStar Deluxe
On the official website
Get SingStar Deluxe songs (some of these sites refer to torrents)