Daylight Savings Time Starts in US/Canada on March 10, 2012
If you live in the USA or Canada, Daylight Savings Time 2012 starts on March 11, 2012. This means that, at 2 am, we "spring forward" and lose an hour of sleep but gain an hour of daylight.
Basically, in the early hours of Sunday, March 11, the clock will go from 1:59 am to 3:00 am.
The first day of Spring isn't until March 20, so you can keep wearing that moose sweater for another week.
States and territories that do not observe DST
Arizona, Hawaii, American Samoa, Guam, Puerto Rico, and the Virgin Islands; as well as most of Saskatchewan and some parts of BC, Nunavut and Quebec, do not observe Daylight Savings Time.
iPhone Users, Beware of Daylight Savings Time
If you use your smartphone as your alarm clock, we suggest switching the phone to manual time settings and adjusting the time yourself if you actually have to be somewhere on March 10. If you're an adult, Daylight Savings Time is not a valid excuse for being late to work.
The iPhone has famously failed with DST more than once. With Android, it's better safe than sorry, since your random handset's firmware may choose March 10 as International Screw My Owner Day.