For most Linux distributions, you can find background info and links to update your system for the upcoming Daylight Saving Time changes at http://www.linux-watch.com/news/NS6300294422.html. For those of you with Gentoo, just an "emerge sys-libs/timezone-data" should do the trick.
Apple users should refer to http://docs.info.apple.com/article.html?artnum=305056 to find patches or instructions to fix the DST changes manually, depending on your OS version. You will also find links on that page containing special instructions to update your Java and WebObjects environments.
For everyone, Sun has posted DST instructions for Java at http://java.com/en/download/faq/dst.xml. In certain cases (but not all) you may wish to remove older versions of Java if you update to the latest and greatest. Directions for that process may be found at http://www.java.com/en/download/faq/5000070400.xml.
For those just joining in, the original post concerning DST updates for Windows, Windows Mobile, Outlook etc may be found at http://netdef.livejournal.com/20027.html.
Deadline for doing these updates is this coming Saturday, March 10th. If you miss the deadline, don't panic. You can still do the updates at any time, but your calendars and clocks may not show the correct time until you complete the task.