OSX 10.4 (Tiger) and 10.5 (Leopard) only.
iChat in OSX 10.6 and above has this configuration built in.
You can use Apple's iChat (OSX Tiger and Leopard) to connect to the Google Talk service. Google and iChat use the "Jabber" instant messaging system for this. You don't need to be logged in to Google Mail or even have your web browser running. Depending on the speed of your Internet connection, you may use the audio and/or video features of iChat via Google Talk, assuming you have the proper equipment on your Mac.
First Time Running iChat?
I have used iChat on this Mac before (e.g.: with Bonjour or my AIM or .Mac account).
If this is the first time you have tried to run iChat on your Mac, you will have to go through an initial iChat set-up process. Here are the steps:
The first thing you will see is the Welcome to iChat AV screen:
Just click Continue.
Next comes the Set up iChat Instant Messaging screen:
Your name should already be filled in here.
For Account Type select AIM Account from the pull-down menu. This may seem a little confusing. It looks as if you have to have an AIM or .Mac account before going any further, but that's not the case, as you will see in the next step.
Leave the Account Name and Password fields blank.
Next comes the screen where you can Set Up Jabber Instant Messaging:
Check the Use Jabber Instant Messaging box.
For Account Name enter your full Gmail (Google Mail) email address, including the @gmail.com part.
Optional: Enter your Gmail email Password. Your password will be remembered in the Mac's Keychain. For security reasons you may choose to leave this blank, in which case you will be prompted for your Gmail password each time you start iChat and log in to the Gmail Jabber account.
Next comes the screen where you can Set Up Bonjour Instant Messaging:
Bonjour is Apple's facility for (among other things) easy set-up and communication among Macs and printers on the same local area network (LAN). If you have more than one Mac connected to your household or small office LAN, and you want to use iChat in this setting, then check the Use Bonjour Instant Messaging box. Otherwise, leave this box cleared.
If your Mac has a camera attached you will see the Set Up iChat AV screen:
Smile and click Continue. Note that you can change the picture quite easily later on.
Finally, you will be at the Conclusion screen:
Click Done. But you are not quite finished yet; iChat will try (unsuccessfully) to connect to the Google server.
Keep going, below.
From the iChat menu select Preferences:
When the Preferences screen opens,
Click Accounts along the top of the screen.
Select your Gmail account from the list on the left of the screen (it may already be selected).
Now click Server Settings and enter values as shown below.
Check the boxes next to Connect using SSL and Allow self-signed certificates.
According to Google your password is always secure when using Google Talk, so you don't need to check the box next to Warn before password is sent insecurely.
The Location field must not be empty. Either enter iChat here or check the Use my machine name box.
After closing the Preferences screen, you may have to select Log in to Jabber from the iChat menu to connect to Google Talk.
Done! You may wish to add iChat as a Login Item (under Accounts in System Preferences) so that iChat will start each time you log in to your Mac.