Hi, I'm another of Mark Guzdial's GATech Squeaker. The first major project I've actually completed is a full instant messaging client for Squeak. This instant messaging client has backwards compatibility with ICQ and AIM so you won't have to have a separate client just to host these other protocols. The instant messaging client also as support for squeak->squeak object messaging. You can easily do stuff like sending over a RectangleMorph simply by dragging and dropping.
Oh well, enough about my IWIN (that's the name) client. If you want more info, please visit http://instantmessaging.swiki.net