This adds to information that is available on the community xchat help page showing the way in which to connect to the Ubuntu classroom and the Beginners Team help channel.
Once you have followed that page and started xchat, you should find that the Ubuntu servers are available in the network list, which makes life a bit easier, if not use the Freenode server to get access to the ubuntu channels.
Once you've started it for the first time you should have a window similar to that shown in the first attachment open.
You can see that I have mine set up with the 3 nicks I have registered, I also have it set to skip the network list and to start with the channels I want.
Once you have set up the first screen, select the Ubuntu servers and then edit, you should now have a new window similar to the second attachment.
Here you can see that I have 3 options selected - it is not necessary to have these selected, but this is the only server I connect to and I do want it to start without any prompts from me.
The important parts here are the Favorite channels and Nickserv password.
In the channel box you can put in channels which will connect on start, if you wanted to connect to the Ubuntu classroom and the Beginners Team help channel you would put, replace them with any of the ubuntu channels and you should get there instead.
Note there is no gap between the , delimiter
If you have registered you nick with Nickserv as suggested on the xchat community page, you can put it here and it will be used when you start xchat. Once you have closed the edit window you can use the connect button to connect to the channels in your list.
If you prefer to do so, there is a java chat applet available on the Classroom wiki page which will connect you to the classroom.
Obviously there are many more IRC channels available - many of the Ubuntu channels are referenced here
The Beginners Team live in #ubuntuforums-beginners and will always help when asked.