How to Configure iChat in Mac OS X Snow Leopard
By default, iChat uses the MobileMe account that you set up when you first installed Mac OS X. In this case, your MobileMe account name and password are entered automatically for you, and you’re good to go. When you first run iChat, you’re prompted to create an iChat account. The basic iChat configuration steps are included here.
Click iChat in the Dock.
If this is the first time you've opened iChat, a form opens for you to enter your information.
Type the first name (your name) that you want to use in the First Name field, press Tab, and then type the surname that you want to use.
iChat displays the Buddy List window and sets up Bonjour messaging automatically.
(Optional) Change your photo.
By default, iChat uses your user account thumbnail image as your visual persona. However, you can add a picture to your iChat identity by dragging an image to the well next to your name at the top of the Buddy List window. If necessary, iChat asks you to position and size the image so that it fits in the (admittedly limited) space.
Check out the buttons along the bottom of the Buddy List window:
Add a New Buddy
Start a Text Chat (plain, old-fashioned chatting via the keyboard)
Start an Audio Chat (chatting with your voice, using microphones)
Start a Video Chat (the ultimate chat, where the parties can both see and hear each other)
Start Screen Sharing (where you can view, or even remotely control, a Buddy’s computer)
These buttons handle about 90 percent of the commands that you need to give while using iChat. (Note that the Bonjour window doesn’t have an Add a New Buddy button because the Buddy list in the Bonjour window is populated automatically by other iChat folks on your local network.)
When you’re running iChat, you can choose to add a balloon menu bar icon in the upper-right corner of your screen. You can change your online/offline status, immediately invite a Buddy for a chat, or display the Buddy list. The menu bar icon appears only if you enable the Show Status in Menu Bar check box. Click iChat in the menu and choose Preferences; then click the General button in the Preferences dialog.