In Gmail and Google Docs, each user can now see all the other users from their business, school or organization in their contact list, making it easier to communicate and share with contacts by just typing the first few letters of people's names.
Editions impacted:
Standard, Premier, Education and Partner Editions
Languages impacted:
US English
How to access what's new:
In Gmail or Google Docs, compose a message or share a document and type the first few letters of a contact's name in the Gmail to: field or the Google Docs sharing box. Contacts from your domain will auto-complete.
For more information:
http://google.com/support/a/users/bin/answer.py?answer=6597
