I’ve had my iPhone for about 5 months now, but only recently I decided to subscribe to MobileMe and try over the air syncing of my contacts and calendar data. Unfortunately, after following Apple’s instructions, I could not get it to work.
My Mac would sync with MobileMe and vice versa, but MobileMe would not push to my iPhone and no could new data was sent from my iPhone back to MobileMe.
Since I rarely connect my iPhone to my Mac (instead using wifi for everything), this was a big problem.
– turn off email sync with my MobileMe account (@me.com) and then turn on the sync with calendars, contacts, and bookmarks.
After this step, sync started almost immediately. I then tried to create a test event on the iPhone and within minutes my Mac was asking me to add it to iCal.
YMMV, but this is how I finally got it working. Since I don’t use the provided MobileMe email account (I instead use Gmail IMAP) turning off that email account wasn’t an issue, but this may still be a deal breaker for some.
If you’re having this issue, hopefully these steps help out.