I don't know wake-on-lan very well, but it seems to be very interesting.
One time I tried enabling it on my PC. At that time, I didn't have anything LAN, but my 56K modem was there. And guess what? Each time I received a phone call, the PC did start by itself!
I suppose it would be the same with a LAN plug (because of the name). Imagine: each time the phone or the LAN has activity, the PC powers up, see if there's an incoming fax or LAN connexion, and when all's done, calls the halt command.
I'll do this one day on my EPIA