Hi, I was going to ask the very same question but then had a lightbulb moment

If you hook up your iPhone to iTunes ready to sync simply create a blank 'new' calendar in iCal and just select that blank calendar in the sync selections in iTunes and at the bottom of the iTunes screen where it gives you the option to replace the calendar entries on the phone, just put a tick by calendar (but ensure you've only selected the blank calendar to sync further up the iTunes screen)! Good luck - I've just done it as I've installed Google Sync on mine via Exchange Server and I can now sync contacts and appointments wirelessly from Google without having to pay a hefty fee to Me.com!!! Good luck.