How do I manage multiple chat windows at once?
Collapse: To collapse a chat window so that just the conversation status bar appears, click the grey space next to your friend's name. Collapsed chat windows offer privacy, without having to leave the conversation.
Stack: If you have multiple chat windows open, Google Talk will stack them in chronological order (the person with whom you started talking first appears at the top of the stack).
Tear off: You can tear chats off of your stack, starting from the bottom window. Drag and drop chat windows into a new stack if you would like to re-prioritise your conversations or you can simply place the windows on another part of your screen.