As I have posted before, the upcoming DST changes in the U.S. are approaching rapidly. I posted a set of useful links. Today, I came across the following article which repeats much of the same information:
TheServerSide.com: Countdown to DST 2007

What is nice about this article is it includes the source to a simple Java program you can use to test whether the DST calculations are working correctly on a particular machine. There is also source to a JUnit test to verify the date manipulation as well.