Windows Home Server is intended to be a headless system.  That means that the box has no monitor, keyboard, or mouse attached.  To administer it, you connect to it from one of the client machines via the Windows Home Server Console.

You can quickly get to the Console window by right clicking the WHS icon in the taskbar next to the system clock.

Clicking the Windows Home Server Console menu item brings up the login screen for the WHS Console.

Following the login process, your WHS Console panel opens.  From here you can change all of your WHS settings.

The first tab is the Computers & Backup tab.

As you can see in the image above, I have 5 computers in my Windows Home Server network.  The ones in black are the currently-online computers.  Here we have the Windows XP Home laptop that I am currently on, the 64-bit Windows Vista laptop, and the 64-bit Windows Vista Ultimate Media Center.  There status on the right reflects the backup situation.  As you can see, all three of these machines are backed up.

The machine called Mark-PC and OFFICEDEPOT laptops are both off.  In fact, the OFFICEDEPOT laptop is no longer on the network and can be removed at any time.

Highlighting any of these machines enables a toolbar across the top where I can view backups, perform a manual backup now, change backup settings, and remove a computer.