You can use NetStumber with your GPS to get
a geo-plot of Access Points in your area.
I used NetStumber to collect the GPS location
data, then imported it into a neat little
program by Doug Cox call USAPhotoMaps. It
downloads topo maps from Microsoft's TerraServer
Web (unfortunately some very old data here).
Doug's website is http://jdmcox.com. Below is a plot of my wardriving trip around
my neighborhood. As you can see, the topo
map was taken before the houses were built.
However, some of the other sections are pretty
up to date. Green dots indicate "open"
(unencrypted) APs while red dots indicate
that encryption is enabled (I have many carelss
neighbors!!)
Enjoy!