They show up as "To Do" items in iCal, not calendar events, so you need to open that drawer (via the pushpin at bottom right in Snow Leopard's version, at least). Also, if you have moved on to the new MobileMe calendar system, you're out of luck at the moment because Apple didn't hook it up to the old framework that Omni uses to communicate with the calendar system. See Ken's post
here for more details.