You may find some ideas and assistance at Houses for the Next Millennium and Architecture . This is a site by kids for kids that helps to explain the Y2K problem. This website was designed as a companion to their TV series of the same same. In addition, there is an extensive teaching guide which provides thematic coverage and additional resources for teachers. Here you can connect to the 'Millennium Moment' plus access the archives for the entire year.
Site also features a countdown calendar and lots of other articles on the approaching millennium.
That's what the Yak is calling this next thousand years, as this site for kids focuses on the problems facing future generations and finding solutions. Here you can look at predictions for the future, and submit your own. Here you can read an article that summarizes World events in AD 1000. This is the official website for Olympics 2000, scheduled for September 15th to October 1st in Sydney, Australia. Here you find links which can be used in preparing classroom activities to the year 2000.