Time Zone information

[Charlie Hawkins2]

I am currently running several DL360g5 machines running Windows 2008, 2 running 2003, several client servers running XP. The time zones needs to run on Indian East. My basic question is, because of Indiana's time zone changes in the past, What is my best option. Running these servers on Eastern Time(UTC -5) or Indiana Time(UTC -5). Both are listed in the timezone area and both of these are -5utc. Could there be any storage of past timezone information in the CMOS or Windows time platform for this Indiana Time Zone to fluctuate DST / EST?