I picked this one on Macintouch:
Tekserve's Aaron Freimark sent us [Macintouch] a tip that may help with Mac OS X 10.2.4's date/time bug:
People who have lost the time after updating to 10.2.4 may find that many files in the /usr/share/zoneinfo directory are corrupt (zero length). Replace them with copies from a Mac that isn't having the problem, and everything gets fixed.
An easy way to check to see if you have this problem is to look in your Date & Time Preference Pane, in the Time Zone tab. If it claims you are in GMT, and you're really not, you have corrupt zoneinfo files. I've tried this on a couple of Macs, and it works.
This command should work to copy the files (type it on the Mac with the busted time):sudo scp -r email@example.com:/usr/share/zoneinfo /usr/share/Substitute "126.96.36.199" with the IP address of a Mac with good files on your network (Remote Login must be on) and "username" means a user on that Mac. Note that there are only four spaces in the above command -- type carefully!