ntp 1:4.2.0a+stable-9ubuntu2 (amd64 binary) in ubuntu feisty

 NTP, the Network Time Protocol, is used to keep computer clocks accurate
 over the Internet, or by following an accurate hardware receiver which
 interprets GPS, DCF-77, NIST or similar time signals.
 .
 This package contains control programs which can access a remote NTP
 server. Thus you will need either ntp-simple or ntp-refclock;
 ntp-refclock includes drivers for radio clocks.
 .
 For more information about the NTP protocol / NTP server configuration
 and operation, load the optional Debian package 'ntp-doc'.