Having switched from Windows Mobile 6.1 to an iPhone I have found that many features are missing from the iPhone that most consider standard in Windows Mobile.  Like the ability for 3rd party applications to access the calendar.  The lack of this in the iPhone seems to be a big mistake on the part of Apple.  They want to push the iPhone as corporate friendly with their exchange support but in reality, it is lacking true corporate support.

I have worked with corporations that do not use exchange servers.  This being said, I am going to give a quick run down on how I sync Google Calendar (used by several companies I have worked for) to my iPhone.  The biggest issue with how I sync is that none of it can be done OTA.  When I had WM6.1 I could sync OTA my tasks, contacts, and calendar, so the loss of this was a big obstacle to my adoption of the iPhone.  Currently, I sync the iPhone with Outlook through iTunes and sync Outlook to gCal with SyncMyCal (www.syncmycal.com).  While this is (1) a paid solution ($25) and (2) not an OTA solution, it is getting the job done for me right now.  I am rarely away from my laptop for more then a few hours, I can sync several times a day.

Lets face it, until Apple decides to open the calendar to access by 3rd party apps (GooSync, SyncMyCal Mobile, etc.), the iPhone is going to have mediocre acceptance into the corporate community.  I hope they add this support in the next firmware release.  I doubt Apple will listen to me, but they really need to do this.