Configuring and Using Chat on Linux
Email is great for conversations which are not time critical or do not need a direct answer now. Sometimes, you need to be able to ask someone questions in real time and get replies to get a result. If email can be thought of as sending and receiving letters by post, then a chat (-or more generally instant messaging or IM for short) is more like a telephone conversation. Basically, when you send a chat message, it instantly pops up on your recipient's screen (-assuming they are online, of course) – and they can choose to respond to it or not. Chat is great for just that: chatting.
I find the easiest chat client to configure is Pidgin (-see http://www.pidgin.im/ for more details). You can install this direct from the Ubuntu Software Centre (-search for Pidgin): not only is it straightforward to configure, it will run on most PC platforms including Linux and Windows
Once Pidgin is installed, you can run it from under the "envelope" icon:

Once invoked, a dialogue box will be displayed:

Click on the “Add” button and a new dialogue will display: enter the following information:
Protocol : Google Talk
Username : your google email account
Password : enter your google email account
Remember password : checked

Click on the “Apply” button once completed. If all went well, the following window should be displayed:

To add a new contact (-assuming you know their email address), choose:
Buddies → Add Buddy

The contact will then be contacted and given a chance to accept or decline your invite to “be your buddy”. If they accept, you will see a new line added to the Pidgin window:
You can also setup (in Ubuntu) your chat account under the speech bubble icon in the top right hand corner:

Once open, if you don't see your chat account listed, click on the “Import” button:

Select the desired account and click “OK”:

Once imported, the window should look as follows:

Check (tick) the “Enabled” field, then click “OK”. If all went well, the chat status should be displayed (e.g. “Available”, “Offline”, etc):

Both Ubuntu and Fedora ship with the Empathy chat client as a default: the reason I use Pidgin is because I originally hit problems configuring the version of Empathy received with Ubuntu 10.10 and, in the meantime, I stumbled on Pidgin.
In order to set up Empathy as your chat client in Ubuntu, click on the speech bubble with an “X” in it, in the top right of the Gnome desktop and select “Chat Accounts”

To start Empathy under Fedora, search for the string "emp" in the "Applications" area:

If you do not have an existing chat account, choose the “No, I want a new account” option and click “Forward”

A new dialogue will display asking you what type of chat account you wish to add. Currently, this only allows Jabber account creation, so accept the default and type in your preferred Jabber ID and password:

Empathy will then ask you if you want to automatically be connected to people on the same network as you. Unless you genuinely want to chat to strangers using your ISP, disable this feature and click on the “Apply” button:

The dialogue box will then disappear.If all went OK, then when you start your chat client..

..then you should see your account listed as “online”. If not, pull up your chat account configuration:

Select the account you are having problems with and ensure the following are set under the “Advanced” drop down:
- Encryption required (TLS/SSL) is checked (ticked)
- Server: is set to “talk.google.com”