Chat
Gmail has a built-in Google Chat 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
Send instant messages
Quick steps on using Google Chat to send instant messages and use voice and video chat.
Google Chat Help Center
 Find out more about using IM, voice, and video chat with the Google Talk gadget in Gmail.
Download the Google Talk client
 Download the standalone Google Talk client to chat via IM, voice, or video with users outside your domain,