Set Date and Time in a Cisco device such as router

To view current date/time (must be in priviledge mode):

show clock detail

To set date/time manually (must be in priviledge mode):

clock set 22:55:00 March 29 2009

To set timezone (must be in global config mode):

clock timezone PST -8

To sync date/time from an NTP server (must be in global config mode):

ntp server aaa.bbb.ccc.ddd

or from Cisco 1700 or lower (from global config mode):

sntp server aaa.bab.cac.ddd