Work in the cloud with Google Apps Sync
With Google Apps Sync for Microsoft Outlook®, your mail, contacts, calendar events, Outlook notes, and tasks are stored in your Google account in the cloud and in Outlook on your computer. Google Apps Sync makes sure data is the same in both places by regularly copying, or synchronizing it back and forth. Incoming messages, meeting invitations, and contacts are downloaded from the cloud to Outlook, while changes you make locally sync back up with the cloud. Because the cloud is accessible from anywhere on the Internet (not just from behind your firewall), you can access this information from any computer anywhere—either from Outlook, or by logging in to Google Apps using a web browser.
Access your mail, contacts, calendar, notes, and tasks from anywhere...
... but only data that gets synchronized
Some information, however, doesn't get synchronized with the cloud. This includes Outlook categories, journal entries, and other features that Google Apps doesn't support. You can still use these features in Outlook. But they don't synchronize with the cloud and therefore aren't there when you sign in to your Google Apps interface.
Learn more about what gets synchronized (PDF).
How synchronization works
When you start Outlook and connect to the Internet, Google Apps Sync begins downloading all the new messages, calendar events, contacts, and so on that it detects since you last connected. The download is chronological, so if you last connected on Friday, and now it's Monday, Friday's messages arrive first. Your email, contacts, calendar events, and so on all synchronize concurrently as separate threads (though email generally takes the longest to complete since there's more of it). You can tell synchronization is happening when the Google Apps Sync icon in your system tray is spinning.
If you don't stay connected long enough to complete an entire synchronization, Google Apps Sync downloads what it can. When your connection resumes, it picks up seamlessly from where it left off until it completes the synchronization.