Officially, your Mac can send AirPlay streams, but can’t act as an wireless AirPlay receiver. For receiving AirPlay streams on your Mac, additional software is needed. One of the solutions for that is AirServer, which allows you to mirror your iOS display or stream content from your iOS devices to your Mac. So it works similar to an Apple TV, just on your Mac.
After you’ve installed and started AirServer, your iOS Devices will automatically find your Mac as an AirPlay receiver.
Streaming music from an iOS Device to your Mac
If you stream music, a window on your Mac shows the album covers and you can hear the sound through your Mac speakers. Here are some screenshots (Spotify on the left, Apples Default Music App on the right).
Receiving video content via AirPlay
Of course, you can also stream videos to your Mac. In some cases it didn’t work, but you can check this for yourself with your favourite Apps and the free trial of AirServer (see Some live-streaming apps, like Netflix, do not work with AirServer and YouTube App Playback Issues)
Additionally, you can use AirPlay Mirroring to see the iOS Display “live” on Mac. AirServer offers a simple Record button, for instance for screencasts, including some post production parameters for tweaking the image. Really nice.
AirServer is available for Windows and Mac. You can download and buy it here: www.airserver.com