... of the Royal Observatory's site, Gene:

>> 3. When do the 3rd Millennium and the 21st Century start?
A millennium is an interval of 1000 years and a century is an interval of 100 years. In the Gregorian Calendar, which we use, there is no year zero and the sequence of years near the start runs as follows;

..., 3BC, 2BC, 1BC, 1AD, 2AD, ...

Because there is no year zero, the first year of the calendar ends at the end of the year named 1AD. By a similar argument 100 years will only have elapsed at the end of the year 100AD. Since 2000AD is the 2,000th year of the Christian calendar, it will be the last year of the Second Millennium. So the 3rd Millennium and the 21st Century will begin at the same moment, namely
zero hours UTC (commonly known as GMT) on January 1st 2001. <<

So sayeth the WORLD timekeepers. Good enough for me. ----- jim o\-S