May 23, 2011
When you start iTunes on a computer connected to a local area network, it automatically looks to see if there are other iTunes users on the network who are sharing streaming access to their libraries. If so, you'll find what they're sharing in the Shared area just below the Store area in the left-hand iTunes column. To share streaming access to your own library, use Preferences in the File menu, select the Sharing tab, and then check and select what you wish to share and whether or not you want to require a password for access.
Home Sharing adds the ability to copy contents among up to five computers on your home network, as well as to stream contents among them and to your iOS devices running iOS 4.3 or higher via AirPlay. It gives the household members maximum flexibility in how they manage what they want on their computers when they sync their devices. Use the Advanced menu on the computer to turn Home Sharing on and off, using the same Apple ID for all five computers, and use that ID as well in the iPod app settings to turn on Home Sharing on iPhone, iPad, and iPod touch. (By the way, if you have a second-generation Apple TV you can also share photos with Home Sharing via the Choose Photos to Share command in the Advanced menu.)