My Time Zones were messed up yesterday as well and a few things missing from my online Calendar. What I did was I first set my correct time zone in the online preferences on MobileMe. Then I went into MobileMe preferences and reset all my Calendar sync data. I set it to override everything online with what is on my iCal. After that everything was right, even new posts.
MobileMe Preferences ---> Sync ---> Advanced ---> Reset Sync Data
(Make sure you set the override the right way! ical overides MobileMe)
My"Push" is averaging about 15 min on Calendar items. I know it is not what I want or expected, but in reality, if I need it "right away", 1 sec to click the sync now button on my task bar is not that bad.
Also, setting sync to "Automatically" does not mean "immediately". Although I know that is what we wanted and I still hope to get.