Unfortunately, yes, it's quite difficult to build a nice small calendar app. Other posts in this thread have nicely summarized the essentials. I've thought about writing one but just don't have the time.

My current solution is to run DateBook6 under the Garnet VM Palm simulator. That's less than perfect; there's no desktop widget, sometimes a new entry shows up on every day until you exit and reenter the app, and for some reason my TravelTracker trips don't get entered into the calendar. And getting it to synchronize with a desktop app (I used to use Pimlical) is truly painful. But it's the best choice I have right now.

Maybe if the rumored Android emulator ever comes live, we can run an Android app. Or maybe I should just break down, get an Android, and root the dang thing.