HOWTO for most Linux distributions

Requires: As root, type the following at a shell:
hwclock --systohc
...and all will be right with the world. Assuming your time zones aren't all screwed up.

ntpdate is part of the ntp suite for networked time synchronization available at
XCthulu: Yes, xntpd will keep your computer's clock closer to Boulder's clock. It can get time via GPS, WWV, dial-up, and the government mind control ray broadcasting service. xntpd will wash your windows and empty the kitty litter. xntpd is a daemon, and like most networking daemons must be properly configured to avoid a security hole. It also has a proud history of remote exploits. ntpdate isn't nearly as slick, and it doesn't understand four day simultaneous time, but it will set your clock to a more reasonable approximation of the current time as most people need without any potential of future security problems.