When run with an appointment as the current item, the code below
prints "Eastern Standard Time" for an appointment created today,
starting and ending later today, during Daylight Saving Time. Both
Windows and Outlook are correctly set to Eastern Time; Windows is set
to adjust automatically for Daylight Saving Time (I cannot find a
separate option for this in Outlook 2010, though I'm sure there
stupidly was one in earlier versions), and the Date and Time
Properties dialog in Windows correctly reports the current time zone
as "Eastern Daylight Time". Any ideas?

Dim objApp As Application
Dim objItem As AppointmentItem
Set objApp = Application
Set objItem = objApp.ActiveInspector.CurrentItem
Debug.Print objItem.StartTimeZone