According to a bulletin from the International Earth Rotation and Reference Systems Service, we are due for a Leap Second at the end of the year. This will help keep our atomic-clock-driven Coordinated Universal Time in line with "solar time". Just like there aren't exactly 365 days in a solar year, there aren't exactly 86400 seconds in a solar day. Unfortunately we cant predict when leap seconds will be needed due to the irregularity of the Earth's rotation, and must rely instead on emergency leap-second bulletins from the good folks mentioned above.
The extra second will be added to the UTC time signal at the end of December 31st, so it will go 23:59:59, 23:59:60, 00:00:00. Hence, those in Greenwich will have an extra second to count down as they ring in the new year. For we Melbournians on Australian Eastern Daylight Time (UTC+11, including the daylight savings hour), we should put our clocks back 1 second at 11:00:00 on January 1, 2006. Failure to do so will result in chaos of millenium-bug proportions!