AimSniff simply gives you the IP of an AOL Instant Messenger user when you make a direct connection with them. All the user needs to do is to make a direct connection with the other user, and once its made simply click on the sniff button and you will have their IP. Then disconnect from that direct connection and you may repeat this with other people.
RequirementsMac OS 9 or later, AIM client.
*Previously available here