A wireless router is great when toting a computer with a wireless
interface around, but moving a wired computer to another room or floor
often means stringing an unsightly Ethernet cable through the house.
The alternative is buying a wireless adapter, hoping that a Linux
driver is available for it (there often isn’t). Even a wireless
interface is no good when used out of range of the wireless router.
Read the rest of Howto set up a Wireless Bridge in Debian (561 words)