From Yahoo news "Wait a second: 2008 gets extended by timekeepers", I know that the year 2008 will be a second longer just like the leap year. The world's time keeper will add a leap second on the last day of 2008.
It is interesting.
Along with the global economy, the earth is slowing down, requiring timekeepers to add an extra second to their atomic clocks to keep in sync with Earth's slightly slowing rotation. So an extra second will be tacked on to Dec. 31 after 6:59:59 p.m. and before 7 p.m. Eastern Standard Time.
the extra second plus the extra day in Februry makes the year 2008 the longest year since 1992.
However, computer operating systems may check with the world's atomic clocks and update their time to add the leap second automatically without special operation.
The world started adding leap seconds in 1972, sometimes twice a year. This is first leap second since Dec. 31, 2005. This is the fourth year to have a leap day and a leap second.