Mibbit
From SHellium Wiki
NOTE: Mibbit has been banned from freenode. You cannot access #shellium in Freenode from Mibbit. However you can use other servers to connect to it!
Mibbit is a very simple web based client which is very easy to use.
All you need is a web browser with JavaScript activated.
Just navigate to the URL: http://www.mibbit.com/chat/
Click "Server", then in the Server address box, type:
irc.freenode.net
In the "Nick" box, type a name you would like to use (Using your real name is highly unadvised)
In the "Channel" box, type:
#shellium
Then click "Go"
You can also create a custom widget, using this link: http://www.mibbit.com/widget.html
The widget is helpful if you would like to provide a chatbox on your own site, or just want fullscreen chat.