If you are in a household with many computers all with their own iTunes libraries, there is a great way to share the music from one computer to another. ITunes now allows you to share your library over your network. Once configured, you will see the library available in the shared section of the left hand panel in iTunes.
Here is how to set it up:
From iTunes, select "Edit" and then "Preferences." Once the Preferences windows opens, select the "sharing" tab, and finally "Share my library on my local network." You are able to select various types of music, videos, and much more. At the bottom, you can also require a password.
All music should stream fine over a 54G wireless connection but you will want a physical connection for video.