Chat (Google Talk)
Gmail has a built-in Google Talk gadget that lets you send instant messages to people in your domain, directly from your email application. You can also chat with people outside your domain using the standalone Google Talk client.
Send instant messages
Quick steps on using Google Talk to send instant messages and use voice and video chat.
Find out more about using IM, voice, and video chat with the Google Talk gadget in Gmail.
Download the standalone Google Talk client to chat via IM, voice, or video with users outside your domain,
Additional Videos including comprehensive Videos on Google Talk in Google Apps have been collected and catalogued in the SOO Video Repository available at this link.