Power Over Ethernet (a.k.a. PoE)
Using the extra wires in a CAT5 cable to carry DC to a device such as an AccessPoint.
Andy Freeman from Geelong, Australia has made a Power over Ethernet module to suit a 5.25inch drive bay. http://kawasaki.kz/wireless/poe.htm
Several vendors are starting to sell ghetto POE solutions quite cheaply.