Yep. Leopard comes with new stuff. Lazeez says it works fine, but commenters here are having trouble.
Tabbed Chatting In iChat
Among the missing features I hear the most complaints about regarding iChat is the lack of tabbed chatting. Today I discovered it’s part of Leopard. Simply go to the iChat prefs, click on the messages pane, and selected “Collect chats into a single window” and you’re set. » about 100 words