When users instant message using Gmail's browser-based chat feature, they can now have multi-user chats, add emoticons to their messages, and view media like YouTube videos right in the chat window.

Editions impacted:
Standard, Premier, Education and Partner Editions

Languages impacted:
US English

How to access what's new:
Sign in to Gmail, and start a chat session with one or more of your contacts. When a contact sends you a YouTube link, you can watch the video right in Gmail's chat window.

For more information:
http://www.google.com/a/help/intl/en/users/talk.html