A lot of people disable the messenger client coz of all the spam you get on it, but its worth a go.
Walkabouts are really hard to make it pinpoint since wireless boxes don't generate a uniform distibution and each one generates a different field, add to that any localized interference, plus wireless cards themselves aren't sensitive enough to make a really good signal field map.
we could give you a lot of information on how to enter their networks, but how do we know you'd use it for good