The calendar that comes built-in to Windows Phone is a great app, but it does have a few niggling little drawbacks.
Now comes a new app, Super Calendar, which has a amazingly high level of functionality. It integrates with Live, Hotmail and Google calendars. It displays your appointments by day, month of year and also offers offers views by day, week, month or year. It provides Lockscreen and Live Tile support.
Supercalendar costs £1.49 and, as usual, you can try it for free at the Windows App store here.