Ah, forgotten about this, could be useful:

search google for nagios and check_ntp_time or check_ntp for some perl code that checks the drift or the status of the NTP server.
Nagios Plugins come with check_ntp.pl (although it works, others say it is deprecated... in favour of faster C compiled ones... I still like the perl version more)

check_ntp_time.pl download

ntp monitors searchpage

Addendum, while on Debian, to synch your time,

ntpdate install and usage

Running ntp while on a laptop (and stopping it while on charge/starting it while charging)