Update: Some of our commenters are reporting that they're also seeing hour-early alarms in parts of North America. It's not yet clear if this is widespread or idiosyncratic, and if all 4.x devices are affected.
Update #2: Engadget points out that alarms set never to repeat, or set to repeat every day, are unaffected; just the selective repeat alarms (only weekends, only weekdays) are getting munged.
The iOS bug that caused recurring alarms to go off an hour early in New Zealand after its switch to Daylight Saving Time subsequently hit some territories in Australia following their switchover a week later. Apple promised a fix to the problem, and it's likely the fix will be bundled with the forthcoming iOS 4.2 update -- but that update hasn't come soon enough to stop the problem from striking Europe. With the switchover to Standard Time in Northern Hemisphere nations, European and Middle Eastern countries that have switched are now experiencing the same problem we saw in New Zealand and Australia, but in reverse: Europeans' recurring alarms are going off an hour later following the switch to Standard Time.
In New Zealand, the issue eventually resolved itself. A couple weeks after the switch to DST, recurring alarms started going off at the correct time again. The going theory was that Apple's time zone programming in iOS relied on obsolete protocols for DST; New Zealand used to switch to DST on the first Sunday in October, but switched to the last Sunday in September in 2007. It's possible the issue may eventually sort itself out in Europe as well, but not before a lot of Europeans who rely on their iPhones to wake them wind up late for work.