Just wanting to share that..
We use an Apple Airport Express to wirelessly play Itunes on a BC9500 at home and today I've got myself a program called Airfoil and I think it's great.
Following information comes from their website:
Send any audio from your Mac to AirPort Express units, Apple TVs, iPhones and iPods Touch, and even other Macs and PCs, all in sync! Airfoil for Mac gives you your audio, all around the house.
Greets, Beoblok