NOTE: The real plugin author is emilles. I've just copied this plugin from the forum to add-on's section of the site.

Features

• Supports a wide range of AirPlay devices and programs
• Streams audio to multiple supported devices over wired or wireless network(s)
• Synchronizes audio streams between multiple devices
• Displays track metadata (title, artist, album, artwork, progress) on devices that support it
• Supports full set of playback operations (play, pause, stop, seek, skip, etc.)
• Plays multiple tracks with no gap between tracks
• Supports remote control
• Supports password-protected remote speakers
• Supports multi-homed (more than one network interface) workstations
• Discovers remote speakers automatically using zero-configuration network protocols
• Supports static configuration of remote speakers for hard-to-locate devices
• Supports international characters for device names
• Supports mono and stereo input
  Supports standard sample rates (samples per second) on input
  Supports standard sample sizes (bits per sample) on input