We just started Daylight Saving Time in New Zealand yesterday. Since then, many iOS users here have experienced what's probably one of the weirdest bugs I've ever seen: our alarms are now going off an hour early. My iPhone's alarm woke me up at 5:50 in the morning today instead of 6:50, and it turns out I'm not the only one.
In the iPhone's built-in Clock app, setting a recurring alarm will cause it to trigger an hour early every time if you're running iOS 4.1, iTunes 10.0.1, and live in a Southern Hemisphere country that's just gone over to Daylight Saving Time (which, for now at least, just means New Zealand). It's also been affecting US users in Indiana since late June because of the weird time zone situation in that state. For some reason, non-recurring alarms aren't affected; so far, changing recurring alarms to non-recurring is the only thing that's fixed the problem.
Standard Time doesn't start in the US until November 7, which is right around the time that iOS 4.2 is supposed to come out. Since this bug is probably something that can only be addressed by an iOS update, and since a relatively small portion of iOS users will be affected, I won't be surprised at all if Apple sits on this bug until November and bundles the fix into iOS 4.2. Meanwhile, Australian iOS users in territories that observe DST will have something to look forward to: unless this gets fixed before October 3rd, their alarms are going to start going off an hour earlier, too.