How can obtain the IP of contact wich is stored in my contact list?
Most clients I’‘ve tried don’'t give you this option.
The admin can get them from the admin control panel
The reason for that can be found in the url=http://www.xmpp.org/specs/rfc3920.html#security-clientXMPP spec[/url] as you can see below:
“The IP address and method of access of clients MUST NOT be made public by a server, nor are any connections other than the original server connection required. This helps to protect the client’'s server from direct attack or identification by third parties.”
That means that most probably XMPP compatible clients/servers will not provide support for this. However, you can write your a new server plugin that provides the required information through an XMPP extension.