I'm assuming since you are on the BackTrack site you can at least set up a laptop with a compatable wireless card and the live cd.
Using a decent wireless card you can browse the neighborhood's AP's and check client MAC addresses using Kismet. When in Kismet looking at the AP's available hit the s key then the p key. This will sort the AP's by they're packet count. The higher the power and packet count the closer and more active the AP is. Now just scroll down to the AP you want to check and hit enter, then you will see detailed info. on the AP your checking. If it has clients/laptop connected you can see there MAC addresses by hitting shift+c keys. If they have your Laptop and are using it, you will see your MAC address.
You can also integrate a GPS unit with Kismet to have the Access Points plotted on a map for you but I would need all your hardware info. to explain how.
If you don't know how to setup BackTrack, your NIC, or Kismet just let me know and I'll check back later with help if you need it, good luck.