Google launched their Sync software for iPhone and Windows Mobile-based devices.
This software will allow automatic Gmail and Google calendar syncing. The Google Sync uses push technology, so every change will automatically be synced with your mobile device.
Of course, Google Sync works both ways and you’ll be able to alter your Google account details from your mobile device. The Sync software already works for BlackBerry, S60, S40 and Sony Ericsson devices.