Handling timzone is quite simple in Asp.Net applications. First thing,   you should always store DateTime values in the DB in one timezone (UTC is most commonly used).  This eliminates many conversion issues.

Here is the sample code..

DateTime time1 = new DateTime(2008, 12, 11, 6, 0, 0);  // your DataTimeVariable 
TimeZoneInfo timeZone1 = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time"); 
TimeZoneInfo timeZone2 = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time"); 
DateTime newTime = TimeZoneInfo.ConvertTime(time1, timeZone1, timeZone2);

Get all available/supported Timezones in .Net TimeZoneInfo class

      foreach (var tz in TimeZoneInfo.GetSystemTimeZones())
            {
                Response.Write(tz.DisplayName + " is Id =','" + tz.Id + "'");
                Response.Write("<br>");
            }