This looks like it might be usable.
You can find out when beacons hear you, and compare your signal reports with 
another station to see how well you are getting out in to many different 
locations.
I saw register, log in, and PayPal links.  Don't know if it is a service fee 
or donation page.

If this works, their would be many good uses for it.

http://www.reversebeacon.net/
H T Kaufman MSW LCSW
Adaptive Technology Instructor