Airfoil
Commercial
Airfoil streams any audio from your computer, from music services like Spotify and Pandora.
WiFi Audio Wireless Speaker is an android app to play music wirelessly.
TuneBlade
Commercial
TuneBlade is a software to stream audio to Airport Express, Apple TV, AirPlay compatible speakers and HiFi Receivers.
Stream What You Hear
Open Source
Stream What You Hear is a Windows software to broadcast the sound of your computer.
Compare AirPlay with alternatives
Compare WiFi Audio Wireless Speaker and AirPlay and decide which is most suitable for you.
Compare Stream What You Hear and AirPlay and decide which is most suitable for you.