I finished reading my linguistics so I thought I'd goof off for awhile and do that myself. I only wish I was so clever to think of it in the first place. :P
I found this gem, tonegen.c, changed the -t parameter to specify tenths of seconds instead of seconds, then wrote a minimalist Perl script to repeatedly call iwconfig, parse out the Link Quality $s from my wireless network card, then play a tone of 80+$s**1.3 Hertz for 0.1 seconds.
The result is that I can now walk around the house and hear the signal strength varying in an almost-continual tone.
But of course the real reason is so I can drive around neighborhoods/businesses with my laptop in my front seat and "listen" to where other people have wireless base stations. When I finish my linguistics homework, I think I'll go do just that. :P
I think Evan said the guy had a GPS receiver hooked into his laptop also, and it'd record where it found base stations at the same time. I suppose if I had a GPS system it'd only be another 5 lines of Perl.