Hardware Secrets posted a guide about building a wireless network using a broadband router

More and more people are willing to assemble their own wireless network. With a wireless network set at your home or office, you will be able to share files, use the printer and access the Internet without the need of connecting a network cable to your computers. This is great if you have desktop computers located in places where is hard to install a network cable or if you want to have the freedom to access your network and the Internet using your laptop anywhere inside your home or office: you can carry your laptop from your bedroom or office to your living room and it will still be connected with no cables attached.

How to Build a Wireless Network Using a Broadband Router