So I just upgraded my original iPhone to 3.0 and it’s working great so far. The thing that I was most waiting for with 3.0 was the ability to connect to both my Exchange calendar at work and my personal Google Calendar. It only took a few minutes to get it setup. After deleting my former Exchange connection from my phone to Google Calendar, I setup a new Exchange connection to our server, enabling Mail and Calendar. After that, I setup a new CalDAV account for Google Calendar. The settings that worked for me were:
Once you save the settings, tap on the Advanced Settings button and confirm that Use SSL is turned on to ensure that your account credentials are being passed to Google over an encrypted connection.