If you have a networked PC integrated into your home theater system, it's easy to use iTunes with Home Sharing enabled to distribute music and other content to up five PCs, Macs, or laptops in the home network. This sharing takes place in the background. In other words, you can be listening to other music in iTunes, watching an iTunes TV show or movie on the big screen, or just using the PC with iTunes minimized. As long as iTunes is running and the computer is on, sharing is enabled as far as the network reaches. Sharing files in the background over the network is much easier than using "sneaker-net" (using a thumb drive to manually distribute iTunes content).
Our test network consisted of a Windows Vista PC hooked to the Internet via a TrendNet wireless router. This desktop PC has 1.5 TB of media storage and acts as the server. On the wireless network are a Windows 7 notebook and a Windows XP notebook. The system was set up purposively to be as simplified a system as possible. No single computer is the "boss" computer, and the network is intended to share and share alike, even if one or more PCs are absent from the network. (You can read about how the network was set up here.)
It's been possible to share iTunes folders over Windows networks for a while now, but only with some inconveniences from Apple's DRM scheme. Home Sharing eases the burden considerably, making setup as simple as logging into your sharing account and promising to share all of your content, including previously purchased DRMed music.