This applies to the U.S and Canada. As you know Daylight Savings Time is being extended. You will need to install an update on your computers so that they change times on the correct dates. I'm not sure much bad can happen on home machines except goofed up e-mail times for a few weeks and such, but you never know. Also, you may want to check with your corporate IT people to make sure they got your work computers covered.
You can read more about it and download the updates here:
http://www.microsoft.com/dst2007
