iPhone users aren't waking up on time due to a Daylight Saving Time (DST) bug. Even though the iOS clock changes correctly, the alarm does not.
Last month, users down under were woken up an hour early due to an iOS bug that caused recurring alarms to go off at the wrong time after the DST switch. It started in New Zealand and eventually hit some territories in Australia following their DST change a week later. It looks like Americans and Europeans are facing similar issues today, according to hundreds of messages on Twitter. Europeans have it the worst though: while the other regions are being woken up an hour early, those in Europe are being woken up an hour late. As a result, many are not making it to work or school on time.
It is rather shocking that Apple hasn't addressed this issue in a timely fashion (pun intended). After it happened the first time, the company promised to fix the problem, and we expect it will do so in the upcoming iOS 4.2 update (along with other bug fixes) but there's no telling when that will be. Many think the problem is that Apple's time zone programming in iOS relies on obsolete protocols for DST.