[Greg Jones]

OmniFocus will sync its Actions (tasks) to the To Do (tasks) list in iCal. First, ensure that you have synced the tasks (File>Synchronize with iCal) as syncing to iCal is not automatic. If you click on the push-pin in iCal, I expect you will see the tasks that have synced.

Syncing will not create new events, with alarms, in iCal from the tasks contained in OmniFocus, if that was the behavior you were expecting. Events and tasks are not the same thing, so they cannot directly sync to/from iCal and OmniFocus.

On my system I have set up Growl to give me notifications when Actions that have an assigned start date/time are available. For me this provides the same functionality as what I get for alarms of events in iCal. I don't sync anything from OmniFocus to iCal, although I do use a script available here in the Extras forum to move over the occasional action that needs to be made into an event.