Fake AirTunes with a Laptop? 

I've decided what I really need in life is a little application that runs on my laptop that's hooked up to my stereo. This would make iTunes think that my laptop was an Airport Express, and my laptop would show up as remote speakers in iTunes.

Then, I could play music on my main computer in part of my house, have it streamed over to the laptop going through my stereo, and I'd have the whole house covered. It would rock.

It must happen.

It might work via Remote Desktop, but I'm not sure how well the audio streaming works. I'll have to try it out. But I can't be the only person to think of this idea, right? Some enterprising young person must have already written this code and have it on a website for like $19.99 for me to buy, right?

Find me that person. Make me happy.