Sync Google calendar with Google Sync
Google has just release a new tool called Google Sync, a service that syncs your contacts and Calendar wirelessly to your iPhone, BlackBerry, Symbian, or Windows Mobile phone.
Google Sync uses a Microsoft Exchange server to keep all of your contact and calendar data in sync over the air. If you’ve added a new calendar appointment from your desktop, Google Sync will push the update to your phone. Likewise, changes you make from your phone are automatically synced to your Google account in the cloud.
Google Sync Beta for your mobile phone [via Official Google Mobile Blog]