I found the way how to track the yahoo user who is chatting with you.. Please follow the method as i have described below you can get his/her location like Country/State/City/Region and many more information..
simple method 1
make a simple script page in asp,php,jsp or any that logs in the remote user ip. then get the ip and do a query on whois.net.
you can get the geographical ip address.
simple method 2
send him an email and make him reply. check the headers.
all methods can give you his physical ip address and if is in a network you wont get his physical computer access.
if you want to get his ip for any sort of trojan attack/script attact etc.. this info isnt really useful.
By method 1 if he/she replies by the mail. In yahoo when you open the mail scroll down on right side you will find the Full header link click it the you will get all the information about the mail find the field [Received: from [188.8.131.52]] this is what the ip address copy this ip address then go to the site http://www.maxmind.com/app/locate_ip and paste the address and press the submit button you will get all the information.
For example:- i received the mail, then i clicked on Full header link i got the folowing information
X-Apparently-To: firstname.lastname@example.org via 184.108.40.206; Wed, 28 Jun 2006 21:19:01 +0530
Authentication-Results: mta117.mail.in.yahoo.com from=yahoo.com; domainkeys=pass (ok)
Received: from 220.127.116.11 (HELO web42103.mail.mud.yahoo.com) (18.104.22.168) by mta117.mail.in.yahoo.com with SMTP; Wed, 28 Jun 2006 21:19:00 +0530
Received: (qmail 33042 invoked by uid 60001); 28 Jun 2006 15:48:58 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:
Received: from [22.214.171.124] by web42103.mail.mud.yahoo.com via HTTP; Wed, 28 Jun 2006 08:48:58 PDT
Date: Wed, 28 Jun 2006 08:48:58 -0700 (PDT)
From: Send an Instant Message "h b"
Yahoo! DomainKeys has confirmed that this message was sent by yahoo.com. Learn more
Subject: me (dont give to else)
Content-Type: multipart/mixed; boundary="0-1255100025-1151509738=:32596"
I found the received from field i.e Received: from [126.96.36.199].
When i copied and pasted this ip address
in http://www.maxmind.com/app/locate_ip i found all the information
Like Hostname,Country Name,City,State etc..