How to Transfer Calendar to iPhone 4
How to Sync IPhone with Outlook Calendar using iTunes
1 .Open iTunes and ensure you have the latest version.
2. Connect your iPhone to your PC/Laptop using the cable It will automatically launch iTunes. Then choose "iPhone" from the iTunes source list. Click on the "Info" tab in iTunes.
3. Click on the "Sync Outlook calendars" option. Then in the lower-right corner of your screen click “Apply”.
Your PC/Laptop will now sync with your iPhone based on your settings.
FYI: Make sure calendars are stored in Outlook 2003 or Outlook 2007 compatible calendar application.
Another way to sync Outlook Calendar to your iPhone is through Google Gmail service. Outlook should be synced to Gmail, then your iPhone can wirelessly sync to Gmail through the Google Mobile Apps application, which can be found in App Store on your iPhone.
The calendar syncing program for Google, "Google Calendar Sync," is compatible with Outlook 2003 and 2007.
Hope this helps.