Before you sync your iPhone with MobileMe, you must do some setup. The next two procedures describe what to do.
Before setting any MobileMe options on your iPhone, do the following:
Make sure you are running the latest versions of iTunes, iPhone software, and MobileMe System Preferences.
Check your data in Address Book and iCal; make sure that they are all up to date and backed up.
Connect your iPhone to your Mac. Select your iPhone from Devices in the iTunes sidebar. Click the Info tab.
As you have not yet configured MobileMe on your iPhone, you will see a message about setting up MobileMe with a Set Up Now button that links to http://www.apple.com/mobileme/setup. Don't bother with it; follow the instructions here instead. ...