All datetime fields, including event due dates, object creation and modification dates, and others, are now shown in the user's local timezone. This should make deciphering datetimes a little easier for those of us who don't live in Greenwich.
Update: The .ics feeds for My Tasks and My Events are now timezone-aware too. This shouldn't change how they behave, but will help some calendaring apps like iCal display event times in the user's local timezone. It also allows me to add alarms to events and tasks, which I've done and will be announcing in the next post.