http://www.tuaw.com/2008/07/28/mobileme-the-case-of-the-vanishing-iphone-contacts/
Another day, another new way for MobileMe to anger folks. Today we are hearing lots of grumbling about people seeing their contacts and calendars disappearing from their iPhones after a sync with MobileMe. Luckily, it looks like it is only the iPhone that is wiped, the contacts/events are still on their Macs.