Google Apps Business & Education users can now find any user in their company
Lookup allows Google Apps for Business and Google Apps for Education users to find and contact any user in their corporate domain. Users can type or speak name, domain alias (e.g., jdoe) or email address, and Lookup will find the contact information for the user from the Global Address List and provide rich, structured contact data. Users can tap to contact the person via email, chat, phone or open a map of the address.
Lookup supports Android versions 2.1 - 2.3.x devices and requires the "Shared Contacts" feature enabled by the organization administrator in the Google Apps Control Panel. Android version 3.0 and above has the same functionality built-in, so you won't need to use this app.