AnalogX - Atomic Time Sync
Queries the NIST NTP server to set the computer clock to the exact time.
AtomSync
A background utility that periodically checks a PCs clock against an internet NTP time server or against a computer in a LAN (local network) which runs an AtomSync LAN time server.
Chrony
A Unix-based NTP implementation specifically written to be suitable for computers with dial-up connections to the Internet.
CHU Time Synchronization for Linux
Software to synchronize a Linux system to the Canadian CHU shortwave station.
Clocks and Time: Time Software for PCs
Lists PC based software for time setting and synchronization, clock rate correction and time display.
ExactClock
Software and hardware to keep computer clock synchronized to the Atomic Clock over the Internet.
FACTS
A freeware GUI-based SNTP client for the Amiga, which will synchronize system time to a server across the Internet. It is also capable of automatically switching in and out of DST.
Java Clock Applet
Supports network synchronization via SNTP, HTTP, Time, and Daytime protocols. Free download.
JSNTP?
A free, cross-platform Java application that uses Simple Network Time Protocol(SNTP) to accurately synchronize your computer's clock with NTP servers.
Klox
Windows 9x/NT freeware decorative desktop clock, with different faces and Internet time server syncronization.
Network Time Protocol (NTP) Project
Links to many time service clients from the maintainer of the NTP. Includes non-NTP clients.
Sync-It with Atom
Network Time Protocol client for Windows with a nice user interface.
TymServ
Time reference that draws from multiple time sources. Computer networks and systems can be automatically synchronized.
WorldClock
Allows the user to synchronize his or her PC to Internet time servers. Supports both the Time or SNTP protocols. Also provides timezone, alarm and calendar features.