What is Google Apps Sync?
Google Apps Sync for Microsoft Outlook is a plug-in for Outlook 2003 or 2007 that lets you import your existing data from Exchange (or any other hosted service you use Outlook with) into Google Apps. You can then keep using your familiar Outlook interface to manage your Google Apps mail, calendar, and contacts. Or you can switch to using the Google Apps interface in a web browser.
Google Apps Sync seamlessly syncs all your Google Apps mail, calendar events, and contacts between your Google Apps account in the cloud and your Google profile in Outlook, so you can access the same information at any time from either interface.