How could I possibly not know about this? This is, without a doubt, the coolest thing I've stumbled upon on the web in a long time.
While I was Google-ing "Al Stewart karaoke," I came up with the hit for Singshot. You can record your own versions of songs and there are contests and voting and it's like karaoke night right on your desktop.
I sang my own version of "Yesterday" which was horrendous, but, the beauty of karaoke is that, every version I listened to was at least as awful as mine. There are also some very good singers out there.
Man, I need to open me up a karaoke/sushi bar. Yeah, that's the ticket.