As the subject says, I now have Media Center 15 streaming to Airplay devices. It works, albeit it will cost you about $80, and it's not exactly elegant....
You will need:
1. Your favorite JRiver media program
2. A copy of Rogue Amoeba's Airfoil for windows ($30)
3. A copy NTONYX's Virtual Audio Cable v4. ($50)
You can get along without the VAC, but it works better if you have it.
What we need to do:
1. If you purchased VAC, create one virtual audio card for every "zone" you'll want in MC. If you don't have VAC, you only have one zone.
2. Start Airfoil and tell it to to airplay the virtual audio card for the zone you want. I have not convinced it to handle multiple VACs, but Rogue Amoeba says this can be done through the SDK.
3. Start MC, and create a zone of your choice, and bind it to the virtual audio card you created in step 1
It's not pretty, but it does work -- now you can stream MC content to any Airport express, Apple TV, etc. Rogue Amoeba events makes an Airplay client for your iPod/iPhone/iPad.
What we really want:
The ability to have MC and Airfoil work wiht multiple zones in the background under SDK control.