Microsoft Knowledge Base Article 914837 contains the following summary and introduction:
SUMMARYOn April 2, 2006, Indiana will start using daylight saving time. Most counties in Indiana will use the Eastern Time zone. However, some counties will use the Central Time zone.
The time zone setting for Microsoft Windows will change from Indiana (East) to either Eastern Time (US & Canada) or Central Time (US & Canada). The Indiana (East) time zone setting will become obsolete and should not be used in the future. Indiana residents should use local sources of information to determine the correct time zone.
This article describes issues that are related to the time zone changes in Indiana. This article also describes how and when to change the
time zone setting. How you make this change depends on whether you must change one computer or many computers.
INTRODUCTIONOn April 2, 2006, all counties in Indiana will start using daylight saving time. Residents who are in the Eastern Time zone will set clocks forward one hour on that day to start using Eastern Time. Residents who are in the Central Time zone will not change their clocks on April 2, 2006, but will start using Central Time.
Currently, Microsoft Windows products contain the (GMT -5:00) Indiana (East) time zone setting. This setting does not use daylight saving time. You must update Windows-based computers in the affected time zones as follows:
|•||If you are in a county that will use the Eastern Time zone, set your time zone to Eastern Time (US & Canada) as soon as possible. If you do this, new meetings or appointments that repeat and that you set up between now and April 2, 2006, will be accurate.|
|•||If you are in a county that will use the Central Time zone, we recommend that you do not change your time zone until April 2, 2006. This step helps prevent the wrong offset for meeting requests between now and April 2. On April 2, change your time zone to Central Time (US & Canada), and then reset your clock to the correct time. After this change, you may have to update or resend requests for meetings that repeat and then verify other meeting requests in your calendar programs.|
Note You should use local information to determine which counties will use Central Time and which counties will use Eastern Time.