Last year, Google rolled out a way for BlackBerry users to sync Gmail and Google Calendar contacts to their devices, but today Google announced it is rolling out a beta of Google Sync for iPhone and Windows Mobile devices. The application enables users to push their Gmail contacts and Google Calendar items directly to their mobile devices. For iPhones, Windows Mobile devices, and phones that support SyncML (like most Symbian S60 devices and many Sony Ericsson phones), the synchronization is two-way, meaning updates to made either on Google’s services or the phone are automatically matched up "within minutes." Google Sync’s connection is always on, so updates are automatic regardless of users’ locations or activities.
Google envisions Google Sync being most useful for folks who use Google Apps and other Google tools regularly, like business and schools tied in with Google Apps, or families who rely on Gmail and Google Calendar. The synchronization process is all-or-nothing: syncing via Google Sync will replace all existing contact and calendar information in the mobile device, so users should be sure they want to use the service before getting started. There are also known issues for both the iPhone and Windows Mobile devices.
[Update: An interesting tidbit: Google licensed Microsoft’s Exchange ActiveSync protocol for Google Sync, making Google and Microsoft rather unusual partners in the project. Of course, Microsoft describes the deal as an example of its willingness to license its technology and intellectual property.]