Dil:Timezone is the issue
Really? Because in your example you have a date with no time. If you are using .Net 3.5 you can do something like:
DateTime oldTime = new DateTime(2007, 6, 23, 10, 0, 0);
TimeZoneInfo timeZone1 = TimeZoneInfo.FindSystemTimeZoneById("Mountain Standard Time");
TimeZoneInfo timeZone2 = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");
DateTime newTime = TimeZoneInfo.ConvertTime(oldTime, timeZone1, timeZone2);
Otherwise it's more difficult with Daylight Savings time being the monkeywrench in the works.