SyncJe from NextHaus is another option for syncing calendar info to SyncML, although I think the price is way too high right now. I'd suggest waiting a week or two for the iPhone 2.0 software update. There might be some kind of built in syncing (although it may require subscription for .Mac/MobileMe) or at least you could install an application like SyncJe (if they release it in the App Store, the price will be much cheaper).