tracing ips

[dep]

greets!

i'm endeavoring to determine the whereabouts -- the city would 
probably be adequate -- of a cable modem with a particular ip 
address, the equivalent of "whereis" instead of "whois." anybody know 
how to do this?

it is a matter of considerable delicacy, so if anyone who can aid me 
would contact me offlist, i'd appreciate it.

thanks.
-- 
dep

http://www.linuxandmain.com -- outside the box, barely within the 
envelope, and no animated paperclip anywhere.