I have an Airport Express that I have plugged into a speaker system. I can change the music in my house with my iPhone through Apple's Remote app. Great.
Now is my Airport Express compatible with AirPlay? Can I 'push' music or sound to my Airport Express and out the speakers that are plugged into it? Or is this only possible with an Apple TV? And if I get an Apple TV can I do what I'm trying to do? 'Push' music from someone's iPhone that is on the same WIFI network as mine to a speaker system?