Ok, folks.  I'd like to invite you to download and play with my Chat Client. 
I got the server running on my home machine and I believe it is reachable 
from the net.   For now it is Windows only, unless someone can build a VM 
for other platforms from the supplied image.

You can get the zip file and instructions from here: 
http://wiki.squeak.org/squeak/6011

Enjoy!

Here are the instructions, reproduced:
Instructions for the Chat Client
Note The server is running on my machine and I will be gone for a week after 
catching a flight in about 3 hours. Hopefully it will work (fingers 
crossed). If not, I will fix it when I get back and we can try again.

Installation After unzipping the zip file, run the image with the supplied 
VM.

Configure The tricky part is setting up the networking code so that others 
can connect to you. Every image is a server, in this peer to peer system. If 
your machine is behind a router, then you will need to specify the external 
ip address to your router, and make your machine the DMZ. I don't currently 
support host names, but that is next on the list.

To configure your network settings, there is a #squeakelib page in the 
Preferences Browser. Go there and there are three settings.

Automatically update your ip address. This is useful if you are directly 
connected to the internet and use DHCP. Every time the image starts up, it 
will recalibrate to the current ip address. Don't use this if you are 
manually setting your ip address, below.
Manually set your ip address. If you are behind a router, find out it's 
external ip address and enter it here. This way, references to objects that 
you send out will be resolved to the router. Also make your router pass 
through to your machine as the DMZ.
Manually set your port. This will override the default, which is 11061.

Running Chat
At the top of the window, there is a button which says: 'SqueakElib Chat 
Launcher'. Click this button. It will prompt you for a nickname. Then the 
launcher window will open. There are two List panes. The top one is for 
other users. If luck is with us all, you will see a list of the other users 
signed on, in the top pane. You can right click and select 'open chat' to 
start chatting with the other user. The bottom pane is for multiway chats. 
You can create a multiway chat and start chatting. Or you can select an 
existing multiway chat and join it and start chatting.

Hacking There are ways to be malicious. I would ask that you explore, but 
not try and change the system.

Enjoy!!