Google Sync also provides two-way contacts synchronisation for devices that support SyncML, such as most Sony Ericsson handsets and Nokia models based on Symbian S60 2nd and 3rd edition.
It was previously made available for BlackBerry.
"Sync uses push technology so any changes or additions to your calendar or contacts are reflected on your device in minutes," observed Google Mobile software engineer Bryan Mawhinney. "The connection is always on so you don't have to manually sync your phone after Sync has been set up."
Google Sync is still in beta, and it appears to be a genuine beta (as opposed to 'we're calling it a beta because we don't want to imply that it's production-quality') since several "known limitations" (aka bugs) are listed.
Examples include changes to meeting attendees made on a Windows Mobile device not syncing back to the server, and syncing more than five calendars to an iPhone results in them all being displayed in the same colour.
"We're constantly working on improvements," Google officials noted.
Microsoft welcomed Google's implicit endorsement.
"Google's licensing of these Microsoft patents relating to the Microsoft Exchange ActiveSync protocol is a clear acknowledgement of the innovation taking place at Microsoft," said Horacio Gutierrez, Microsoft's deputy general counsel and VP, intellectual property and licensing.
Google previously added CalDAV support to Google Calendar allowing two-way synchronisation between Calendar and applications such as Apple's iCal. Synchronisation between the Mac's Address Book application and Google Contacts has been available since Mac OS X 10.5.3.