Understanding Home Sharing
Home Sharing in iTunes is designed to let you easily share your iTunes media libraries between up to five computers in your household. You can also use Home Sharing to play your iTunes content on your iOS devices and Apple TV (2nd generation) if they are connected to your home Wi-Fi network.
Home Sharing your iTunes libraries among your family computers
Home Sharing enables you to stream or transfer music, movies, TV shows, apps, and more among up to five authorized computers in your household. To do so, you will need to Turn on Home Sharing on each computer using the same Apple ID. Once set up, all the libraries from your computers you've enabled Home Sharing on will show up in the SHARED area of iTunes:
With Home Sharing, you can stream music and video from one authorized computer to another, or simply drag music between computer libraries. You can also choose to have iTunes automatically import purchases you make on any of your Home Sharing computers to your own library. To do so, select the library and use the Settings button at the lower right of the iTunes window to check what you'd like copied.
Home Sharing your iTunes library with your iPhone, iPad, iPod touch and Apple TV (2nd generation)
Home Sharing can also extend streaming of music, movies, TV shows, and more to your iOS devices and Apple TV (2nd generation). To stream music, movies, TV shows, and more to the multiple iPhone, iPad, and iPod touch devices in your family, as well as your Apple TV (2nd generation), you will need to turn on Home Sharing on the devices. You'll also need to use the same Apple ID on each device on your home Wi-Fi network.
Note: iOS 4.3 or later is required for Home Sharing on iOS, and Apple TV (2nd generation)or later for Apple TV.
For more information on minimum requirements and how to setup or troubleshoot an iTunes Home Share for your household, visit the Home Sharing support page at http://www.apple.com/support/homesharing.