i dont know if this is illegal were you live (and yea i now this topics old but its for everyone else out there im posting this)
programs like Cain and Abel work very well.....
if you can get direct access to it heres what you do:
Cain and Abel
ok, plug into the router
read guides on how to find the pass to the router (this is really simple but make sure you have a good suply of dictionary attack txt's
otherwise brute force the damn thing :P
usually though the pass is REALLY easy to crack becuase admins dont use proper time to protect there crap.
i really suggest a dictionary attack since bruteforce is freakishly slow considering its just exuasting possibilties
once you find the pass go to the address bar and type:
192.168.1.1 (if thats the routers ip)
get whats rightfully yours WITHOUT changing the pass
there you go its really that simple though if your trying to do something illigal then heres MY disclamer right now:
what you do with the information is YOUR problem and not mine and i will not be held responcible.