does anyone knows how to trace a yahoo chater's ip ??

hi i am looking to find a little software that is able to trace a yahoo messenger chater's ip does anyone know ???
thanks in advance
peter

Politeish:
Yahoo chat? Via an instant messenger thing, or by Yahoo web-based IRC? If it's a quasi-irc connection, you can try "/whois Username". Could you be more specific?

Flamey:
But why would you want this information? What good reason do you have? Can you use a spellchecker?