Hi Grant, My Linux boxes have usually logged a message like:
Jul 1 00:59:59 aturing kernel: [3812251.350269] Clock: inserting leap
second 23:59:60 UTC
This message is logged by the kernel, so you can see it in the
output of dmesg - otherwise check in /var/log as it should have
been logged to some one of the files there.
David.

