iPhone and Exchange 2003 Calander Issues
Our company was having issues with the calendars not syncing between iPhones and Outlook clients.
The primary issue was appointments created on the iPhone were not being added to the desktop Outlook clients. However, you could see the event if you viewed your calendar in list view or logged into the Outlook Web Access. They just didn't show up in the usual month or week views.
After some searching it appears it was related to beginning times for appointments not being set. You could create reoccurring appointments and they would show up fine.
The solution for us turned out to be a patch for Exchange 2003: KB958781. Some recurring calendar items disappear from the "Day/Week/Month" view in Outlook when a user uses Exchange ActiveSync on a mobile device to modify a recurring meeting in an Exchange 2003 environment.
After application of this patch, appointments added from iPhone now correctly showed up on Outlook clients.