You do not need any software or any special setup to use a router. You plug a cable into the router, plug the other end into the iBook, and you're done.
To configure software, just start the computer, and you'll probably be online immediately. If you start the computer and you aren't online, just run System Preferences from the Dock, click on Network, and where it says Show: choose Built-In Ethernet. Then make sure it says Configure: Using DHCP. That's all there is to it!