You can use italki's chat system. I guess you have to have your pop-up blocker disabled, because it's a pop-up window. In general you can only talk with your friends, but it depends on the individual settings of each person. To initiate a chat session, press "Chat now" on the person's profile page (somewhere on the right). Make sure the person is online at that time. Then the pop-up window appears both on your screen and on the other person's screen, and you wait for the person to see it and respond, if they want to :) Or you can exchange messenger IDs or Skype IDs with your friends (some people have them posted on their profile page under Contact information) and commonly agree upon an hour when you are both available to chat on that other system. Good luck!