for security reasons the clients-server multiplayer games don't transmit the IP of the players.
the IP addresses are available (easily or not) only with peer2peer games, in short those games where the architecture doesn't use a real primary server but all the clients communicate with the others directly.
an example are some DirectPlay games.
in those that use the Gamespy peerchat server the IP addresses of all the players are easily visible because peerchat is just a simple IRC server so a whois /player gives all the needed informations (the IP is obfuscated, you must use my peerchat_ip tool to deobfuscate it).
and then exist some very rare clients-server games that have or had the IP addresses available in the replies of the information queries and indeed they caused security risks:
http://aluigi.org/adv/aa2k7x-adv.txtwell, I hope this quick and little list of info can be useful