http://www.microsoft.com/downloads/details.aspx?FamilyID=196fe38c-df20-4e19-92ca-6bda7bec3ecb&DisplayLang=en

Overview

Windows® Home Server will automatically backup your home computers to the home server and allow you to easily restore the entire computer or an individual file or folder to a previous point in time. The Windows Home Server Backup solution backs up only the data that has not already been backed up. Even if you have several copies of the same data on different computers, the data is backed up only once on your home server and your home server keeps track of what data was stored on each home computer on each day. This makes it efficient in the time it takes for backups to complete and the amount of space that is used on your home server.