I just tested the Apollo IM Version Negative 1, which is touted as an early beta but is actually probably an early alpha. Although it actually loads my buddy list on after the login information's entered, it only loads a portion of the contacts. But it does manage to send messages.
Once you do manage to load a chat screen with a buddy that happens to there (thanks, Adam Frucci), there are some amateur features/early bugs like having to hit a button to bring up the keyboard, and being able edit the chat history. This version is a fantastic proof of concept, but definitely a lousy chat client.
Oh, and the first IRC client has been released as well. But unless this is 1999 again, most of you will have no use for this. But you can make IRC commands and chat, so there's that.
You can install both with Installer.app, which you can see how to use here.