http://www.infoplease.com/spot/daylight1.html
If anybody around here is like me, you didn't even realize this was about to happen. When DST starts and ends in the US officially changes this year to extend DST by about a month total. The question becomes, will this have any impact on any of your web or other applications that you use? It is likely worth checking with your vendors to find out. It's a little thing, but a lot of people like to see the proper timestamps when they are on your pages.
The types of applications I can think of right off the top that 'could' be impacted are forums, blogs or just about anything that allows people to sign up for an account to allow posting and asks for their timezone information in an effort to show the correct time when they, or others posted something. Decent chance that there are other types of apps that rely on this data as well.
If this is something that may be of concern to you, you've got just under a month to figure it out. The new version of DST starts March 11th.