Leopard styled iChat!
This cool free iChat add-on might not give you everything the Leopard version of iChat gives you but there are still many Leopard exclusive features. You basically won't get the backdrops or iChat theater, but you can get great features such as tabbed chat windows and a lot of other customization possibilities. You can get iChat to set your status to "Away" automatically when the screen-saver starts, you can get Growl notifications, you can set a notification message when you quit iChat and there are still active conversations, you can auto-accept text invitations or incoming files (you can set to accept only files from a certain group to reduce the security threats) and you can get notifications in your Dock. The feature that really got me to download it is the tabbed chat, but I can tell you that I started liking all the customization options after a while. You can download Chax here on MacUpdate. Once it is installed, you can set the preferences in the iChat preferences. A new tab called "Chax" will be added in the preferences. Screenshot from MacUpdate: