Daylight Savings Time is different this year for people in the US. It starts March 11th. What this means can be a simple as your computers being an hour off to being out of compliance with laws that could get you and your organization into big trouble.
If you have XP, you should be okay. There are certain areas of the world, that require an additional download, but you should be doing checks for downloads on a regular basis. Windows 2000 computers do require updating and older versions of Linux also require help. Here is a good article on what to do with Linux server.